CVE-2026-5545

MEDIUMNVD 6.56.5
EchelonGraph scoreMEDIUM confidence

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

Score 6.5 from GitHub Security Advisory published 2026-05-13. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
6.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 6.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host.

libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead.

When reusing a connection a range of criteria must be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials.

An application that first uses Negotiate authentication to a server with user1:password1 and then does another operation to the same server asking for any authentication method but for user2:password2 (while the previous connection is still alive) - the second request gets confused and wrongly reuses the same connection and sends the new request over that connection thinking it uses a mix of user1's and user2's credentials when it is in fact still using the connection authenticated for user1...

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
The EG Score, 6.5 of 10.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
0.5%
EPSS %ILE
41st
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (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

May 13, 2026

Last Modified

September 15, 2026

Advisory Details (3)

Auto-updated Jun 14, 2026
Patch available.
Web page

curl - wrong reuse of HTTP Negotiate connection - CVE-2026-5545

https://curl.se/docs/CVE-2026-5545.html

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibcurl4-openssl-dev (7.81.0-1ubuntu1.24) @ jammy2026-09-15ubuntu
ubuntulibcurl4-openssl-dev (7.68.0-1ubuntu2.25+esm5) @ focal2026-09-15ubuntu
redhatcurl-main-8.20.0-0.1.hum12026-05-02redhat

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

(7 across 7 ecosystems)
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.10.6 up to 8.14.1-r3: fixed in 8.14.1-r3
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.10.6 up to 8.20.0-r0: fixed in 8.20.0-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.10.6 up to 8.20.0-r0: fixed in 8.20.0-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
curl7.74.0-1.3 ... 8.9.1-2~bpo12+1 (219 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
curl7.88.1-10 ... 8.9.1-2~bpo12+1 (184 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
curl8.14.1-2, 8.14.1-2+deb13u1, 8.14.1-2+deb13u2, 8.14.1-2+deb13u2~bpo13+1, 8.14.1-2+deb13u3
  • every version up to 8.14.1-2+deb13u4: fixed in 8.14.1-2+deb13u4
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
curl8.14.1-2 ... 8.20.0~rc1-1+exp3 (45 versions)
  • every version up to 8.20.0~rc2-1: fixed in 8.20.0~rc2-1
—

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 11× in last 7d / 34× 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 258 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 158 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  2. 2026-10-12 15:55 UTCEG score recompute
  3. 2026-10-11 19:39 UTCEG score recompute
  4. 2026-10-11 16:54 UTCEG score recompute
  5. 2026-10-11 14:17 UTCEG score recompute
  6. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  7. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  8. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  9. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  10. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  11. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  12. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  13. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  14. 2026-10-04 22:48 UTCOSV refresh
  15. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  16. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  18. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  19. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  20. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  21. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  22. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  23. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  24. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  25. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 35th percentile
Show 75 more
  1. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  2. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  3. 2026-09-15 07:26 UTCVendor advisory
  4. 2026-09-15 07:26 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  5. 2026-09-15 06:40 UTCEG score recompute
  6. 2026-09-15 06:40 UTCVendor advisory
  7. 2026-09-15 06:40 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  8. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  9. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  10. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  11. 2026-09-11 09:53 UTCOSV refresh
  12. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  13. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  14. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  15. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  16. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  17. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  18. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  19. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  20. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  21. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  22. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  23. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  24. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  25. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  26. 2026-08-23 17:58 UTCEG score recompute
  27. 2026-08-23 17:58 UTCVendor advisory
  28. 2026-08-23 17:58 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  29. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  30. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  31. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  32. 2026-08-20 21:33 UTCEG score recompute
  33. 2026-08-20 21:33 UTCVendor advisory
  34. 2026-08-20 21:33 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  35. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  36. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  37. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  38. 2026-08-17 10:44 UTCEG score recompute
  39. 2026-08-17 10:44 UTCVendor advisory
  40. 2026-08-17 10:44 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  41. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  42. 2026-08-16 04:08 UTCEG score recompute
  43. 2026-08-16 04:08 UTCVendor advisory
  44. 2026-08-16 04:08 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  45. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  46. 2026-08-14 02:36 UTCEG score recompute
  47. 2026-08-14 02:36 UTCVendor advisory
  48. 2026-08-14 02:36 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  49. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  50. 2026-08-12 15:54 UTCEG score recompute
  51. 2026-08-12 15:54 UTCVendor advisory
  52. 2026-08-12 15:54 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  53. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  54. 2026-08-11 02:46 UTCEG score recompute
  55. 2026-08-11 02:46 UTCVendor advisory
  56. 2026-08-11 02:46 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  57. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  58. 2026-08-10 02:25 UTCEG score recompute
  59. 2026-08-10 02:25 UTCVendor advisory
  60. 2026-08-10 02:25 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  61. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  62. 2026-08-09 02:05 UTCEG score recompute
  63. 2026-08-09 02:05 UTCVendor advisory
  64. 2026-08-09 02:05 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  65. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  66. 2026-08-08 01:45 UTCEG score recompute
  67. 2026-08-08 01:45 UTCVendor advisory
  68. 2026-08-08 01:45 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  69. 2026-08-07 01:25 UTCEG score recompute
  70. 2026-08-07 01:25 UTCVendor advisory
  71. 2026-08-07 01:25 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5
  72. 2026-08-06 13:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  73. 2026-08-05 21:43 UTCEG score recompute
  74. 2026-08-05 21:43 UTCVendor advisory
  75. 2026-08-05 21:43 UTCGHSA enrichmentGHSA-6g7g-56fm-f8mp · GitHub CVSS 6.5

Frequently asked(5)

What is CVE-2026-5545?
CVE-2026-5545 is a medium-severity vulnerability; its CVE record was published on May 13, 2026. libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid…
When was the CVE record for CVE-2026-5545 published?
The CVE record for CVE-2026-5545 was published on May 13, 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 15, 2026; the record at its source may have been updated since.
Is CVE-2026-5545 actively exploited?
CVE-2026-5545 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (41st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-5545?
CVE-2026-5545 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-5545?
A fix for CVE-2026-5545 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-5545 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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