Gitea enforces first-time fork contributor approval by blocking jobs, but some job transition and dispatch paths do not re-check the run's approval requirement. A separate run sharing a job-level concurrency group can cancel a pending job and cause its blocked sibling jobs to be re-emitted and dispatched without approval. This allows unreviewed workflow code to execute on self-hosted runners; fork secrets remain withheld and the run token remains read-only.
CVE-2026-66877
HIGHPre-NVD 8.18.1Trending — 4 sources updated this week
EchelonGraph scoreLOW confidence
This high-severity CVE scores 8.1 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.4% (35th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Triggered by: Headline CVSS from CISA-ADP (Vulnrichment) CVSS v3.1
Sources: CISA-ADP (Vulnrichment) CVSS v3.1
8.1EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (the SSVC decision on this page).
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.1Exploit: None knownExposed services: Not assessed
A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).
- CVSS v3
- 8.1
- EG Score
- 8.1HIGHlow confidence
- EG Risk
- 36EG Risk 36/100
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 (value × EchelonGraph’s weight)Severity81% × 45%The EG Score, 8.1 of 10.Exploitation0% × 40%No KEV listing, EG-KEV tier or EPSS when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines; until then, restrict network exposure of the affected system or apply the vendor's mitigation. - EPSS PROB
- 0.4%
- EPSS %ILE
- 35th
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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
October 14, 2026
Last Modified
October 15, 2026
Advisory Details (4)
Auto-updated Oct 14, 2026Fix referenced — no release confirmed yet. Sources: github, github_pr.
GitHub advisoryMentions a patch (unverified)
RCE on self-hosted runners | fork-PR approval gate (`NeedApproval`) bypass via job-level concurrency cancellation · Advisory · go-gitea/gitea · GitHub
https://github.com/go-gitea/gitea/security/advisories/GHSA-v2w8-m4gr-qj65GitHub pull request
fix(actions): enforce fork pull request trust boundaries (#39005)
Fix merged in go-gitea/gitea PR #39018 on 2026-08-21 — awaiting tagged release
https://github.com/go-gitea/gitea/pull/39018GitHub pull request
fix(actions): enforce fork pull request trust boundaries
Fix merged in go-gitea/gitea PR #39005 on 2026-08-21 — awaiting tagged release
https://github.com/go-gitea/gitea/pull/39005Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 8× 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.
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-14 16:30 UTCEG score recomputeFirst assessed: 8.1 HIGH
- 2026-10-14 16:25 UTCNVD updateCVSS v3 → 8.1 · severity → HIGH
- 2026-10-14 15:35 UTCEG score recompute
- 2026-10-14 15:25 UTCNVD update
- 2026-10-14 15:24 UTCMITRE cvelistV5CVSS v3 → 8.1 · severity → HIGH
- 2026-10-14 14:41 UTCEG score recompute
- 2026-10-14 14:39 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-66877?
CVE-2026-66877 is a high-severity vulnerability; its CVE record was published on October 14, 2026. Gitea enforces first-time fork contributor approval by blocking jobs, but some job transition and dispatch paths do not re-check the run's approval requirement. A separate run sharing a job-level concurrency group can cancel a pending job and cause its blocked sibling jobs to be re-emitted and…
When was the CVE record for CVE-2026-66877 published?
The CVE record for CVE-2026-66877 was published on October 14, 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 15, 2026; the record at its source may have been updated since.
Is CVE-2026-66877 actively exploited?
CVE-2026-66877 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (35th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66877?
CVE-2026-66877 has a CVSS v3.1 base score of 8.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-66877?
A fix for CVE-2026-66877 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-66877
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