CVE-2026-53587

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (38th 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
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 7.5Exploit: 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, libgit2 performs a fixed-size strncmp in set_data in src/libgit2/transports/smart_pkt.c without first verifying that the smart-protocol pkt-line capability buffer contains 14 bytes. A malicious Git server can make bytes after the pkt-line complete object-format=, causing format_str to advance beyond the pkt-line and the following memchr length calculation to underflow. The resulting heap out-of-bounds walk can crash a client during the first refs-advertisement packet over HTTP, HTTPS, SSH, or the Git protocol. This issue is fixed in versions 1.8.6 and 1.9.5.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100CISA 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
Severity75% × 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
0.5%
EPSS %ILE
38th
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 d7a9fb87f504 (libgit2/libgit2)

Fix landed in libgit2/libgit2 commit d7a9fb87f504 — awaiting tagged release

https://github.com/libgit2/libgit2/commit/d7a9fb87f504434e9f45228678953c4fa56e7640
github_commit Patch Available

commit affda60c10fc (libgit2/libgit2)

Patch available: libgit2/libgit2 v1.9.5 (contains commit affda60c10fc)

https://github.com/libgit2/libgit2/commit/affda60c10fcef16723451c0d7dc71b71dc20ad3
github_commit Patch Available

commit 2c0ce8c0132a (libgit2/libgit2)

Patch available: libgit2/libgit2 v1.8.6 (contains commit 2c0ce8c0132a)

https://github.com/libgit2/libgit2/commit/2c0ce8c0132ac38ab0db28239462a671e2e5440e
githubMentions a patch (unverified)🟡 PoC Available

libgit2 <= 1.9.4 - Unauthenticated network-reachable heap out-of-bounds read in transports/smart_pkt.c:set_data · Advisory · libgit2/libgit2 · GitHub

https://github.com/libgit2/libgit2/security/advisories/GHSA-pm24-4jhq-3xvm

Vendor Advisories for CVE-2026-53587(6)

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

Patch Availability(7)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibgit2-dev (0.24.1-2ubuntu0.2+esm3) @ xenial2026-10-09ubuntu
redhatrust-0:1.75.0-1.el9_4.12026-09-21redhat
redhatrust-0:1.84.1-1.el9_6.12026-09-21redhat
redhatrust-0:1.84.1-1.el10_0.42026-09-21redhat
redhatrust-0:1.92.0-2.el9_82026-09-14redhat
redhatrust-0:1.92.0-2.el10_22026-09-14redhat
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(4)

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 23× in last 7d / 104× 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 186 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-53587?
CVE-2026-53587 is a high 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, libgit2 performs a fixed-size strncmp in setdata in src/libgit2/transports/smartpkt.c without first…
When was CVE-2026-53587 disclosed?
CVE-2026-53587 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-2026-53587 actively exploited?
CVE-2026-53587 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (38th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53587?
CVE-2026-53587 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-53587?
A fix for CVE-2026-53587 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53587 are linked in the Vendor Advisories panel on this page.

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