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: 0.4%, top 68% of all CVEs by exploit prediction. 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 — Patch released 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%CVSS: 7.5Exploit: Elevated riskExposed: 0

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
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

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%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
32%
KEV
Not listed

Published

August 20, 2026

Last Modified

August 20, 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
github Patch Available🟡 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(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 / EcosystemFixed in / PatchReleasedSource
redhatlibgit2-main-1.9.7-1.hum12026-08-25redhat
ubuntulibgit2-dev (0.28.4+dfsg.1-2ubuntu0.1+esm1) @ focal2026-08-25ubuntu

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.

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 26× in last 7d / 26× 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.

  1. 2026-08-25 16:58 UTCEG score recompute
  2. 2026-08-25 16:58 UTCVendor advisory
  3. 2026-08-25 13:49 UTCEPSS rescore
  4. 2026-08-25 05:07 UTCVendor advisory
  5. 2026-08-24 17:28 UTCEG score recompute
  6. 2026-08-24 17:28 UTCVendor advisory
  7. 2026-08-24 05:50 UTCVendor advisory
  8. 2026-08-23 18:10 UTCVendor advisory
  9. 2026-08-23 06:31 UTCEG score recompute
  10. 2026-08-23 06:31 UTCVendor advisory
  11. 2026-08-23 00:19 UTCEPSS rescore
  12. 2026-08-22 18:53 UTCVendor advisory
  13. 2026-08-22 07:15 UTCEG score recompute
  14. 2026-08-22 07:15 UTCVendor advisory
  15. 2026-08-21 23:49 UTCEPSS rescore
  16. 2026-08-21 19:37 UTCVendor advisory
  17. 2026-08-21 07:59 UTCVendor advisory
  18. 2026-08-20 20:20 UTCEG score recompute
  19. 2026-08-20 20:20 UTCVendor advisory
  20. 2026-08-20 19:22 UTCEG score recompute
  21. 2026-08-20 19:22 UTCVendor advisory
  22. 2026-08-20 19:18 UTCEG score recompute
  23. 2026-08-20 19:18 UTCVendor advisory
  24. 2026-08-20 18:52 UTCEG score recompute
  25. 2026-08-20 18:52 UTCVendor advisory
Show 1 more
  1. 2026-08-20 18:51 UTCMITRE cvelistV5first tracked

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 in the National Vulnerability Database on August 20, 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% probability of exploitation in the next 30 days, which ranks it in the top 68.0% of all scored CVEs.
What is the CVSS score of CVE-2026-53587?
CVE-2026-53587 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-53587?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53587, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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