CVE-2026-53583

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (13th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, verify_server_cert in src/libgit2/streams/openssl.c uses an inverted !!memcmp result in the GEN_IPADD branch when comparing an IP-literal host with a certificate IP SubjectAltName. OpenSSL builds reject matching IP addresses and accept mismatched IP addresses, allowing a network attacker with a CA-trusted certificate containing any IP SubjectAltName to intercept libgit2 connections to IP-literal HTTPS URLs. DNS SubjectAltName validation and non-OpenSSL TLS backends are not affected. This issue is fixed in versions 1.8.6 and 1.9.5.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
60
EG Risk 60/100CISA SSVC

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
Severity65% × 45%
Exploitation40% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
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
0.2%
EPSS %ILE
13th
KEV
Not listed

CISA SSVCTrack 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 public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 20, 2026

Last Modified

September 9, 2026

Advisory Details (6)

Auto-updated Aug 20, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github, github_commit.
github_release Patch Available

libgit2 v1.9.5

Patch available: libgit2/libgit2 v1.9.5

https://github.com/libgit2/libgit2/releases/tag/v1.9.5
github_release Patch Available

libgit2 v1.8.6

Patch available: libgit2/libgit2 v1.8.6

https://github.com/libgit2/libgit2/releases/tag/v1.8.6
github_commit

commit ef086bc3e4ee (libgit2/libgit2)

Fix landed in libgit2/libgit2 commit ef086bc3e4ee — awaiting tagged release

https://github.com/libgit2/libgit2/commit/ef086bc3e4eedf62be38a910381aae24d49871ff
github_commit Patch Available

commit c2aa35409ee0 (libgit2/libgit2)

Patch available: libgit2/libgit2 v1.9.5 (contains commit c2aa35409ee0)

https://github.com/libgit2/libgit2/commit/c2aa35409ee0e6515df64da49750f13a0a42c47f
github_commit Patch Available

commit 647dcb432980 (libgit2/libgit2)

Patch available: libgit2/libgit2 v1.8.6 (contains commit 647dcb432980)

https://github.com/libgit2/libgit2/commit/647dcb432980b84ede4cb5a008bbd1ccb4ead03d
githubMentions a patch (unverified)🟡 PoC Available

Inverted IP SubjectAltName Comparison in OpenSSL Backend ( vuln_1_1_1 ) · Advisory · libgit2/libgit2 · GitHub

https://github.com/libgit2/libgit2/security/advisories/GHSA-h7gc-w2gg-p9xp

Vendor Advisories for CVE-2026-53583(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatlibgit2-main-1.9.7-1.hum12026-08-25redhat

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
libgit21.5.1+ds-1 ... 1.9.7+ds-1 (32 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libgit21.9.0+ds-2
  • every version up to 1.9.0+ds-2+deb13u1: fixed in 1.9.0+ds-2+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libgit21.9.0+ds-2 ... 1.9.4+ds-1 (13 versions)
  • every version up to 1.9.6+ds-1: fixed in 1.9.6+ds-1
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 19× in last 7d / 74× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 123 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-53583?
CVE-2026-53583 is a medium vulnerability published on August 20, 2026. libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, verifyservercert in src/libgit2/streams/openssl.c uses an inverted !!memcmp result in the GEN_IPADD…
When was CVE-2026-53583 disclosed?
CVE-2026-53583 was first published on August 20, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53583 actively exploited?
CVE-2026-53583 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53583?
CVE-2026-53583 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-53583?
A fix for CVE-2026-53583 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53583 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53583

Explore →

Is Your Infrastructure Affected by CVE-2026-53583?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs