CVE-2026-53586

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (20th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-63550 (ENISA EUVD)Source: ENISA EUVD

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: 0.3%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 29/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 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
0.3%
EPSS %ILE
20th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-25). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

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.

The score's inputs: 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

August 20, 2026

Last Modified

October 26, 2026

Advisory Details (6)

Auto-updated Aug 20, 2026
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
GitHub advisoryMentions a patch (unverified)

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-fixtures (1.7.2+ds-1ubuntu3.1) @ noble2026-10-26ubuntu
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 9× in last 7d / 52× 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 169 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 69 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  3. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  4. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  5. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  6. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  7. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  8. 2026-10-26 10:27 UTCEG score recompute
  9. 2026-10-26 10:27 UTCVendor advisory
  10. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  11. 2026-10-25 14:20 UTCEG score recompute
  12. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  13. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  14. 2026-10-22 21:48 UTCEG score recompute
  15. 2026-10-22 21:48 UTCVendor advisory
  16. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  17. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  18. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  19. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  20. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  21. 2026-10-18 03:31 UTCEG score recompute
  22. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  23. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  24. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  25. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
Show 75 more
  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  3. 2026-10-12 15:57 UTCEG score recompute
  4. 2026-10-11 19:40 UTCEG score recompute
  5. 2026-10-11 16:55 UTCEG score recompute
  6. 2026-10-11 14:19 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  10. 2026-10-09 08:21 UTCEG score recompute
  11. 2026-10-09 08:21 UTCVendor advisory
  12. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  13. 2026-10-08 05:55 UTCEG score recompute
  14. 2026-10-08 05:55 UTCVendor advisory
  15. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  16. 2026-10-07 06:53 UTCEG score recompute
  17. 2026-10-07 06:53 UTCVendor advisory
  18. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  19. 2026-10-06 07:52 UTCEG score recompute
  20. 2026-10-06 07:52 UTCVendor advisory
  21. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  22. 2026-10-05 04:58 UTCEG score recompute
  23. 2026-10-05 04:58 UTCVendor advisory
  24. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  25. 2026-10-04 05:38 UTCEG score recompute
  26. 2026-10-04 05:38 UTCVendor advisory
  27. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  28. 2026-10-03 06:37 UTCEG score recompute
  29. 2026-10-03 06:37 UTCVendor advisory
  30. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  31. 2026-10-02 06:49 UTCEG score recompute
  32. 2026-10-02 06:49 UTCVendor advisory
  33. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  34. 2026-10-01 07:13 UTCEG score recompute
  35. 2026-10-01 07:13 UTCVendor advisory
  36. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  37. 2026-09-30 08:11 UTCEG score recompute
  38. 2026-09-30 08:11 UTCVendor advisory
  39. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  40. 2026-09-29 01:53 UTCEG score recompute
  41. 2026-09-29 01:53 UTCVendor advisory
  42. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  43. 2026-09-28 02:00 UTCEG score recompute
  44. 2026-09-28 02:00 UTCVendor advisory
  45. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  46. 2026-09-27 02:57 UTCEG score recompute
  47. 2026-09-27 02:57 UTCVendor advisory
  48. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  49. 2026-09-25 06:24 UTCEG score recompute
  50. 2026-09-25 06:24 UTCVendor advisory
  51. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  52. 2026-09-24 07:22 UTCEG score recompute
  53. 2026-09-24 07:22 UTCVendor advisory
  54. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  55. 2026-09-23 08:22 UTCEG score recompute
  56. 2026-09-23 08:22 UTCVendor advisory
  57. 2026-09-22 09:20 UTCEG score recompute
  58. 2026-09-22 09:20 UTCVendor advisory
  59. 2026-09-21 10:02 UTCEG score recompute
  60. 2026-09-21 10:02 UTCVendor advisory
  61. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  62. 2026-09-20 11:01 UTCEG score recompute
  63. 2026-09-20 11:01 UTCVendor advisory
  64. 2026-09-19 12:00 UTCEG score recompute
  65. 2026-09-19 12:00 UTCVendor advisory
  66. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  67. 2026-09-18 12:59 UTCEG score recompute
  68. 2026-09-18 12:59 UTCVendor advisory
  69. 2026-09-17 13:58 UTCVendor advisory
  70. 2026-09-16 14:57 UTCEG score recompute
  71. 2026-09-16 14:57 UTCVendor advisory
  72. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  73. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  74. 2026-09-15 15:47 UTCEG score recompute
  75. 2026-09-15 15:47 UTCVendor advisory

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

Frequently asked(5)

What is CVE-2026-53586?
CVE-2026-53586 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-53586 published?
The CVE record for CVE-2026-53586 was published on August 20, 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 October 26, 2026; the record at its source may have been updated since.
Is CVE-2026-53586 actively exploited?
CVE-2026-53586 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (20th 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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