Vector is a high-performance observability data pipeline. From 0.10.0 until 0.57.0, the file sink renders its templated path from event fields and opens the result without confining it to an intended directory. When an untrusted source supplies an event field used by the path template, the value can contain an absolute path or parent-directory traversal, causing Vector to create parent directories and create or overwrite files outside the intended location with the Vector process privileges. The resulting file write can modify sensitive files and can lead to code execution when a scheduled task, authorization file, or subsequently executed script is targeted. This issue is fixed in version 0.57.0.
CVE-2026-77621
CRITICALPre-NVD 9.39.3—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.1%, top 35% 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
9.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.3Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.3
- EG Score
- 9.3(medium)
- EG Risk
- 47(Track)EG Risk 47/100SSVC: 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 computedSeverity93% × 45%Exploitation1% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 1%
- EPSS %ILE
- 65%
- KEV
- Not listed
Published
September 22, 2026
Last Modified
September 22, 2026
Advisory Details (5)
Auto-updated Sep 23, 2026Patch available. Sources: github_commit, github_pr, github_release, github.
github Patch Available
Arbitrary file write in the file sink via templated path (path traversal). · Advisory · vectordotdev/vector · GitHub
https://github.com/vectordotdev/vector/security/advisories/GHSA-6342-xwvw-c637github_release Patch Available
v0.57.0
Patch available: vectordotdev/vector v0.57.0
https://github.com/vectordotdev/vector/releases/tag/v0.57.0github_pr
fix(sinks): confinement follow-ups from #25820 codex review
Fix merged in vectordotdev/vector PR #25830 on 2026-07-14 — awaiting tagged release
https://github.com/vectordotdev/vector/pull/25830github_pr
fix(sinks)!: confine routing-field templates to prevent injection
Fix merged in vectordotdev/vector PR #25820 on 2026-07-13 — awaiting tagged release
https://github.com/vectordotdev/vector/pull/25820github_commit
commit 8832452f57af (vectordotdev/vector)
Fix landed in vectordotdev/vector commit 8832452f57af — awaiting tagged release
https://github.com/vectordotdev/vector/commit/8832452f57afb536ea0de53a093f9fd1b669ccecWeakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× 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.
- 2026-09-23 18:08 UTCEG score recompute
- 2026-09-23 17:54 UTCEPSS rescore
- 2026-09-22 16:20 UTCEG score recompute
- 2026-09-22 15:30 UTCEG score recompute
- 2026-09-22 15:29 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-22 · CWE-73
Frequently asked(5)
What is CVE-2026-77621?
CVE-2026-77621 is a critical vulnerability published on September 22, 2026. Vector is a high-performance observability data pipeline. From 0.10.0 until 0.57.0, the file sink renders its templated path from event fields and opens the result without confining it to an intended directory. When an untrusted source supplies an event field used by the path template, the value…
When was CVE-2026-77621 disclosed?
CVE-2026-77621 was first published in the National Vulnerability Database on September 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77621 actively exploited?
CVE-2026-77621 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 35.1% of all scored CVEs.
What is the CVSS score of CVE-2026-77621?
CVE-2026-77621 has a CVSS v3 base score of 9.3 (NVD).
How do I remediate CVE-2026-77621?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77621, 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
Explore the affected products and dependency analysis for CVE-2026-77621
Is Your Infrastructure Affected by CVE-2026-77621?
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