CVE-2026-28780

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-05-06. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
Trending — 4 sources updated this week

Also known asEUVD-2026-27506 (ENISA EUVD) · GHSA-wpww-4qvv-xpv8 (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.4%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server. If mod_proxy_ajp connects to a malicious AJP server this AJP server can send a malicious AJP message back to mod_proxy_ajp and cause it to write 4 attacker controlled bytes after the end of a heap based buffer.

This issue affects Apache HTTP Server: through 2.4.66.

Users are recommended to upgrade to version 2.4.67, which fixes the issue.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
60
EG Risk 60/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
1.4%
EPSS %ILE
71st
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
1.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 5, 2026

Last Modified

September 14, 2026

Advisory Details (13)

Auto-updated Oct 20, 2026
Patch available. Sources: redhat.
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.4 Extended Update Support

https://access.redhat.com/errata/RHSA-2026:36846
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.6 Extended Update Support

https://access.redhat.com/errata/RHSA-2026:36831
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Serv

https://access.redhat.com/errata/RHSA-2026:36373
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:27201
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:27200
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2026:22140
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 10.

https://access.redhat.com/errata/RHSA-2026:21433
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:21391
Web page

oss-security - CVE-2026-28780: Apache HTTP Server: buffer overflow in mod_proxy_ajp via ajp_msg_check_header()

http://www.openwall.com/lists/oss-security/2026/05/05/9
Web pageMentions a patch (unverified)

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

https://httpd.apache.org/security/vulnerabilities_24.html
Red HatMentions a patch (unverified)

2466913 – (CVE-2026-28780) CVE-2026-28780 Apache HTTP Server: mod_proxy_ajp: Apache HTTP Server mod_proxy_ajp: Arbitrary code execution via heap-based buffer overflow

Affected: Red Hat Enterprise Linux 9

https://bugzilla.redhat.com/show_bug.cgi?id=2466913
Red HatMentions a patch (unverified)

cve-details

https://access.redhat.com/security/cve/CVE-2026-28780
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 6",

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28780.json

Patch Availability(14)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibapache2-mod-proxy-uwsgi (2.4.58-1ubuntu8.12) @ noble2026-10-30ubuntu
ubuntulibapache2-mod-proxy-html (1:2.4.7-1ubuntu4.22+esm13) @ trusty2026-10-30ubuntu
redhathttpd-0:2.4.53-11.el9_2.152026-09-14redhat
redhathttpd-0:2.4.57-11.el9_4.52026-09-10redhat
redhathttpd-0:2.4.62-4.el9_6.62026-09-01redhat
redhathttpd-0:2.4.63-1.el10_0.42026-07-28redhat
redhathttpd:2.4-8060020260702195216.ad008a3a2026-07-08redhat
redhathttpd:2.4-8040020260702193120.522a0ee42026-07-08redhat
redhathttpd:2.4-8080020260702200145.63b345852026-07-07redhat
redhathttpd2026-06-22redhat
redhatjbcs-httpd24-httpd-0:2.4.62-13.el7jbcs2026-06-22redhat
redhathttpd:2.4-8100020260519200905.489197e62026-06-01redhat
redhathttpd-0:2.4.62-13.el9_8.12026-05-27redhat
redhathttpd-0:2.4.63-13.el10_2.12026-05-27redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(9 across 9 ecosystems)
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
apache2—
  • every version up to 2.4.67-r0: fixed in 2.4.67-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
apache2—
  • every version up to 2.4.67-r0: fixed in 2.4.67-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
apache2—
  • every version up to 2.4.67-r0: fixed in 2.4.67-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
apache2—
  • every version up to 2.4.67-r0: fixed in 2.4.67-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
apache2—
  • every version up to 2.4.67-r0: fixed in 2.4.67-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
apache22.4.48-3.1 ... 2.4.66-8 (82 versions)
  • every version up to 2.4.67-1~deb11u1: fixed in 2.4.67-1~deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
apache22.4.57-2 ... 2.4.67-1~deb12u1 (46 versions)
  • every version up to 2.4.67-1~deb12u2: fixed in 2.4.67-1~deb12u2
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
apache22.4.65-2 ... 2.4.67-1~deb13u1 (22 versions)
  • every version up to 2.4.67-1~deb13u2: fixed in 2.4.67-1~deb13u2
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
apache22.4.65-2 ... 2.4.67-1~deb13u3 (24 versions)
  • every version up to 2.4.67-1: fixed in 2.4.67-1
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 32× in last 7d / 90× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 98 of 566 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 2 repeat rows among the latest 100 are merged into the row they repeat. The 468 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-30 07:17 UTCEG score recompute
  2. 2026-10-30 07:17 UTCVendor advisory
  3. 2026-10-30 07:17 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-10-29 16:33 UTCEPSS rescoreEPSS 1.4% · 71st percentile
  5. 2026-10-29 08:08 UTCEG score recompute
  6. 2026-10-29 08:08 UTCVendor advisory
  7. 2026-10-29 08:08 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-28 16:32 UTCEPSS rescoreEPSS 1.4% · 71st percentile
  9. 2026-10-28 08:58 UTCEG score recompute
  10. 2026-10-28 08:58 UTCVendor advisory
  11. 2026-10-28 08:58 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-27 16:31 UTCEPSS rescoreEPSS 1.4% · 71st percentile
  13. 2026-10-27 09:13 UTCEG score recompute
  14. 2026-10-27 09:13 UTCVendor advisory
  15. 2026-10-27 09:13 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-10-26 16:31 UTCEPSS rescoreEPSS 1.4% · 71st percentile
  17. 2026-10-26 09:26 UTCEG score recompute
  18. 2026-10-26 09:26 UTCVendor advisory
  19. 2026-10-26 09:26 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-25 16:32 UTCEPSS rescoreEPSS 1.4% · 71st percentile
  21. 2026-10-25 14:37 UTCEG score recompute
  22. 2026-10-25 10:18 UTCEG score recompute
  23. 2026-10-25 10:18 UTCVendor advisory
  24. 2026-10-25 10:18 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-24 16:32 UTCEPSS rescoreEPSS 1.6% · 76th percentile
Show 73 more
  1. 2026-10-24 11:10 UTCEG score recompute
  2. 2026-10-24 11:10 UTCVendor advisory
  3. 2026-10-24 11:09 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-10-23 16:31 UTCEPSS rescoreEPSS 1.6% · 76th percentile
  5. 2026-10-23 11:56 UTCEG score recompute
  6. 2026-10-23 11:56 UTCVendor advisory
  7. 2026-10-23 11:56 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-22 16:34 UTCEPSS rescoreEPSS 1.6% · 76th percentile
  9. 2026-10-22 12:48 UTCEG score recompute
  10. 2026-10-22 12:48 UTCVendor advisory
  11. 2026-10-22 12:47 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-21 16:32 UTCEPSS rescoreEPSS 1.6% · 76th percentile
  13. 2026-10-21 13:39 UTCEG score recompute
  14. 2026-10-21 13:39 UTCVendor advisory
  15. 2026-10-21 13:39 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-10-20 16:32 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  17. 2026-10-20 14:29 UTCEG score recompute
  18. 2026-10-20 14:29 UTCVendor advisory
  19. 2026-10-20 14:29 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-19 16:31 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  21. 2026-10-19 13:25 UTCEG score recompute
  22. 2026-10-19 13:25 UTCVendor advisory
  23. 2026-10-19 13:25 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-10-18 16:31 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  25. 2026-10-18 13:11 UTCVendor advisory
  26. 2026-10-18 13:11 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  27. 2026-10-18 03:50 UTCEG score recompute
  28. 2026-10-17 16:33 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  29. 2026-10-17 14:02 UTCEG score recompute
  30. 2026-10-17 14:02 UTCVendor advisory
  31. 2026-10-17 14:02 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  32. 2026-10-16 16:41 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  33. 2026-10-16 14:52 UTCEG score recompute
  34. 2026-10-16 14:52 UTCVendor advisory
  35. 2026-10-16 14:51 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  36. 2026-10-15 16:31 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  37. 2026-10-15 15:42 UTCEG score recompute
  38. 2026-10-15 15:42 UTCVendor advisory
  39. 2026-10-15 15:41 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  40. 2026-10-14 16:32 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  41. 2026-10-14 09:55 UTCEG score recompute
  42. 2026-10-14 09:55 UTCVendor advisory
  43. 2026-10-14 09:54 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  44. 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  45. 2026-10-13 07:55 UTCEG score recompute
  46. 2026-10-13 07:55 UTCVendor advisory
  47. 2026-10-13 07:54 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  48. 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  49. 2026-10-12 16:16 UTCEG score recompute
  50. 2026-10-12 08:45 UTCVendor advisory
  51. 2026-10-12 08:45 UTCGHSA enrichmentGHSA-wpww-4qvv-xpv8 · GitHub severity CRITICAL · GitHub CVSS 9.8
  52. 2026-10-11 19:58 UTCEG score recompute
  53. 2026-10-11 17:12 UTCEG score recompute
  54. 2026-10-11 14:42 UTCEG score recompute
  55. 2026-10-11 13:48 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  56. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  57. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  58. 2026-10-08 17:11 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  59. 2026-10-07 23:47 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  60. 2026-10-06 15:17 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  61. 2026-10-05 17:42 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  62. 2026-10-03 23:19 UTCOSV refresh
  63. 2026-10-03 14:25 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  64. 2026-10-01 19:49 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  65. 2026-09-30 15:03 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  66. 2026-09-28 13:51 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  67. 2026-09-26 15:58 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  68. 2026-09-26 00:26 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  69. 2026-09-20 20:15 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  70. 2026-09-18 19:27 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  71. 2026-09-17 19:30 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  72. 2026-09-16 14:08 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  73. 2026-09-16 05:15 UTCEPSS rescoreEPSS 1.4% · 70th percentile

Frequently asked(5)

What is CVE-2026-28780?
CVE-2026-28780 is a critical-severity vulnerability; its CVE record was published on May 5, 2026. Heap-based Buffer Overflow vulnerability in modproxyajp of Apache HTTP Server. If modproxyajp connects to a malicious AJP server this AJP server can send a malicious AJP message back to modproxyajp and cause it to write 4 attacker controlled bytes after the end of a heap based buffer. This issue…
When was the CVE record for CVE-2026-28780 published?
The CVE record for CVE-2026-28780 was published on May 5, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 14, 2026; the record at its source may have been updated since.
Is CVE-2026-28780 actively exploited?
CVE-2026-28780 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.4% probability of exploitation in the next 30 days (71st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-28780?
CVE-2026-28780 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-28780?
A fix for CVE-2026-28780 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-28780 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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