CVE-2026-4437

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-03-20. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5; 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
7.5EG
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: 0.3%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 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 partial (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
0.3%
EPSS %ILE
25th
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). 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: 14 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 partial (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)14 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 partial (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

March 20, 2026

Last Modified

October 15, 2026

Advisory Details (1)

Auto-updated Jun 10, 2026
Patch available.
Web page

34014 – (CVE-2026-4437) gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

https://sourceware.org/bugzilla/show_bug.cgi?id=34014

Patch Availability(14)

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

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
glibc2.36-9 ... 2.36-9+deb12u9 (14 versions)
  • every version up to 2.36-9+deb12u14: fixed in 2.36-9+deb12u14
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
glibc2.41-12, 2.41-12+deb13u1, 2.41-12+deb13u2
  • every version up to 2.41-12+deb13u3: fixed in 2.41-12+deb13u3
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
glibc2.41-12 ... 2.42-9 (20 versions)
  • every version up to 2.42-14: fixed in 2.42-14
—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

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 11× in last 7d / 35× 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 100 of 225 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. None are among the latest 100 rows. The 125 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  2. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  3. 2026-10-18 03:39 UTCEG score recompute
  4. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  5. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  6. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  7. 2026-10-15 01:36 UTCEG score recompute
  8. 2026-10-15 01:36 UTCVendor advisory
  9. 2026-10-15 01:36 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  10. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  11. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  12. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  13. 2026-10-12 16:05 UTCEG score recompute
  14. 2026-10-11 19:47 UTCEG score recompute
  15. 2026-10-11 17:01 UTCEG score recompute
  16. 2026-10-11 14:27 UTCEG score recompute
  17. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  18. 2026-10-11 07:55 UTCOSV refresh
  19. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  20. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  21. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  22. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  23. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  24. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  25. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
Show 75 more
  1. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  2. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  3. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  4. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  5. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  6. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  7. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  8. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  9. 2026-09-21 20:18 UTCOSV refresh
  10. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  11. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  12. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  13. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  14. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  15. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  16. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  17. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  18. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  19. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  20. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  21. 2026-09-02 16:38 UTCOSV refresh
  22. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  23. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  24. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  25. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  26. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  27. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  28. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  29. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  30. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  31. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  32. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  33. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  34. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  35. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  36. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  37. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  38. 2026-08-16 11:00 UTCEG score recompute
  39. 2026-08-16 11:00 UTCVendor advisory
  40. 2026-08-16 11:00 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  41. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  42. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  43. 2026-08-14 19:49 UTCVendor advisory
  44. 2026-08-14 19:49 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  45. 2026-08-14 07:10 UTCEG score recompute
  46. 2026-08-14 07:10 UTCVendor advisory
  47. 2026-08-14 07:10 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  48. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  49. 2026-08-12 21:51 UTCEG score recompute
  50. 2026-08-12 21:51 UTCVendor advisory
  51. 2026-08-12 21:51 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  52. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  53. 2026-08-11 21:23 UTCEG score recompute
  54. 2026-08-11 21:23 UTCVendor advisory
  55. 2026-08-11 21:22 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  56. 2026-08-11 04:24 UTCEG score recompute
  57. 2026-08-11 04:24 UTCVendor advisory
  58. 2026-08-11 04:23 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  59. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  60. 2026-08-10 06:30 UTCVendor advisory
  61. 2026-08-10 06:30 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  62. 2026-08-09 18:37 UTCEG score recompute
  63. 2026-08-09 18:37 UTCVendor advisory
  64. 2026-08-09 18:37 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  65. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  66. 2026-08-09 06:44 UTCEG score recompute
  67. 2026-08-09 06:44 UTCVendor advisory
  68. 2026-08-09 06:44 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  69. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  70. 2026-08-08 05:06 UTCVendor advisory
  71. 2026-08-08 05:06 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  72. 2026-08-07 17:13 UTCEG score recompute
  73. 2026-08-07 17:13 UTCVendor advisory
  74. 2026-08-07 17:13 UTCGHSA enrichmentGHSA-m5wq-r4r4-4qrh · GitHub severity HIGH · GitHub CVSS 7.5
  75. 2026-08-06 19:17 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-4437?
CVE-2026-4437 is a high-severity vulnerability; its CVE record was published on March 20, 2026. Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the…
When was CVE-2026-4437 made public?
CVE-2026-4437 was made public on March 20, 2026: that is the date its CVE record's CNA, GNU C Library, gives for when the vulnerability was made public. The CVE record itself was published on March 20, 2026. EchelonGraph's copy of the record carries a last-modified date of October 15, 2026; the record at its source may have been updated since.
Is CVE-2026-4437 actively exploited?
CVE-2026-4437 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-4437?
CVE-2026-4437 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-4437?
A fix for CVE-2026-4437 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-4437 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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