CVE-2026-86320

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-17. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A flaw was found in flatpak-builder where Git hooks are not disabled when applying patch sources with use-git-am: true. An attacker who can provide a malicious source containing a Git post-applypatch hook can cause the hook to execute on the host during the build process, resulting in arbitrary code execution with the privileges of the user running flatpak-builder.

CVSS v3
7.8
EG Score
7.8(high)
EG Risk
51(Track*)
EG Risk 51/100SSVC: Track*

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
Severity78% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
11%
KEV
Not listed

Published

September 17, 2026

Last Modified

September 18, 2026

Advisory Details (3)

Auto-updated Sep 17, 2026
🔬 Proof of concept available. Patch available. Sources: redhat, github.
github Patch Available🟡 PoC Available

CVE-2026-86320: Arbitrary host code execution via git hooks during module source extraction · Advisory · flatpak/flatpak-builder · GitHub

https://github.com/flatpak/flatpak-builder/security/advisories/GHSA-j5p8-jgjc-f3xv
redhat

2471023 – (CVE-2026-86320) CVE-2026-86320 flatpak-builder: Host code execution via `git am` hook execution in patch source extraction (`use-git-am`)

https://bugzilla.redhat.com/show_bug.cgi?id=2471023
redhat Patch Available

CVE-2026-86320 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-86320

Vendor Advisories for CVE-2026-86320(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 29× in last 7d / 40× 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. 2026-09-25 10:22 UTCGHSA enrichment
  2. 2026-09-24 23:00 UTCEG score recompute
  3. 2026-09-24 23:00 UTCGHSA enrichment
  4. 2026-09-24 14:04 UTCEPSS rescore
  5. 2026-09-24 11:38 UTCGHSA enrichment
  6. 2026-09-24 00:15 UTCEG score recompute
  7. 2026-09-24 00:15 UTCGHSA enrichment
  8. 2026-09-23 17:54 UTCEPSS rescore
  9. 2026-09-23 12:53 UTCGHSA enrichment
  10. 2026-09-23 01:31 UTCEG score recompute
  11. 2026-09-23 01:31 UTCGHSA enrichment
  12. 2026-09-22 16:01 UTCEPSS rescore
  13. 2026-09-22 14:08 UTCGHSA enrichment
  14. 2026-09-22 02:46 UTCEG score recompute
  15. 2026-09-22 02:46 UTCGHSA enrichment
  16. 2026-09-21 21:09 UTCEPSS rescore
  17. 2026-09-21 15:24 UTCGHSA enrichment
  18. 2026-09-21 04:02 UTCEG score recompute
  19. 2026-09-21 04:02 UTCGHSA enrichment
  20. 2026-09-20 20:16 UTCEPSS rescore
  21. 2026-09-20 16:39 UTCGHSA enrichment
  22. 2026-09-20 05:16 UTCGHSA enrichment
  23. 2026-09-19 17:54 UTCEG score recompute
  24. 2026-09-19 17:54 UTCGHSA enrichment
  25. 2026-09-19 06:31 UTCEG score recompute
Show 15 more
  1. 2026-09-19 06:31 UTCGHSA enrichment
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 19:09 UTCGHSA enrichment
  4. 2026-09-18 16:43 UTCGHSA enrichment
  5. 2026-09-18 05:21 UTCEG score recompute
  6. 2026-09-18 05:21 UTCGHSA enrichment
  7. 2026-09-17 19:32 UTCEPSS rescore
  8. 2026-09-17 17:59 UTCEG score recompute
  9. 2026-09-17 17:59 UTCGHSA enrichment
  10. 2026-09-17 16:04 UTCGHSA enrichment
  11. 2026-09-17 15:49 UTCEG score recompute
  12. 2026-09-17 15:49 UTCGHSA enrichment
  13. 2026-09-17 08:29 UTCEG score recompute
  14. 2026-09-17 07:34 UTCEG score recompute
  15. 2026-09-17 07:34 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-86320?
CVE-2026-86320 is a high vulnerability published on September 17, 2026. A flaw was found in flatpak-builder where Git hooks are not disabled when applying patch sources with use-git-am: true. An attacker who can provide a malicious source containing a Git post-applypatch hook can cause the hook to execute on the host during the build process, resulting in arbitrary…
When was CVE-2026-86320 disclosed?
CVE-2026-86320 was first published in the National Vulnerability Database on September 17, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-86320 actively exploited?
CVE-2026-86320 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 88.7% of all scored CVEs.
What is the CVSS score of CVE-2026-86320?
CVE-2026-86320 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-86320?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-86320, 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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