CVE-2026-53586

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: 0.5% (39th 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 week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • 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.

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, the built-in HTTP transport in src/libgit2/transports/http.c follows an offsite initial redirect, and handle_remote_auth and handle_auth pass transport->owner->url instead of transport->server.url to the credential callback when the redirected host returns 401 Unauthorized. A callback that scopes credentials to the original trusted URL can therefore return GIT_CREDENTIAL_USERPASS_PLAINTEXT credentials that libgit2 stores in transport->server.cred and sends as an Authorization header to the redirected host. An attacker who controls a trusted Git host or an open redirect on that host can disclose HTTP Basic credentials, personal access tokens, or equivalent credentials. This issue is fixed in versions 1.8.6 and 1.9.5.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100CISA 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%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.5%
EPSS %ILE
39th
KEV
Not listed

CISA SSVCTrack 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). 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, github_commit, github_release.
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 Patch Available

commit c1507abc4464 (libgit2/libgit2)

Patch available: libgit2/libgit2 v1.8.6 (contains commit c1507abc4464)

https://github.com/libgit2/libgit2/commit/c1507abc44647b3acd832a33a5b1c8c9f5ba8821
github_commit Patch Available

commit af2b29ad0a74 (libgit2/libgit2)

Patch available: libgit2/libgit2 v1.9.5 (contains commit af2b29ad0a74)

https://github.com/libgit2/libgit2/commit/af2b29ad0a74d5bac9751376879ddaf848136d3b
github_commit

commit 07de6a7e438f (libgit2/libgit2)

Fix landed in libgit2/libgit2 commit 07de6a7e438f — awaiting tagged release

https://github.com/libgit2/libgit2/commit/07de6a7e438f95ac9a6efd3222a82117e871ed27
githubMentions a patch (unverified)🟡 PoC Available

HTTP transport can leak credentials to an offsite redirect target · Advisory · libgit2/libgit2 · GitHub

https://github.com/libgit2/libgit2/security/advisories/GHSA-2889-x8f6-mc4x

Vendor Advisories for CVE-2026-53586(1)

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

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibgit2-dev (0.19.0-2ubuntu0.4+esm2) @ trusty2026-10-09ubuntu
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(3)

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 21× in last 7d / 79× 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 136 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-53586?
CVE-2026-53586 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, the built-in HTTP transport in src/libgit2/transports/http.c follows an offsite initial redirect, and…
When was CVE-2026-53586 disclosed?
CVE-2026-53586 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-2026-53586 actively exploited?
CVE-2026-53586 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (39th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53586?
CVE-2026-53586 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-2026-53586?
A fix for CVE-2026-53586 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53586 are linked in the Vendor Advisories panel on this page.

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