Vercel deepsec from 0.1.0 before 1.1.17 contains a link following vulnerability in extractTarballLocally that allows sandboxed code to write files outside the sandbox by planting links in result tarballs. Attackers controlling sandbox code, such as a prompt-injected coding agent, can plant symbolic or hard links in the host data directory to write arbitrary files on the orchestrator host.
CVE-2026-109375
MEDIUMPre-NVD 6.16.1Trending — 4 sources updated this week
EchelonGraph scoreHIGH confidence
“—” beside the score: it is equal to the CVSS score beside it.
Score 6.1 from GitHub Security Advisory published 2026-10-12. A secondary CVSS source baseline 6.1; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: GitHub Security Advisory, a secondary CVSS source
6.1EG
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: 6.1Exploit: None knownExposed services: Not assessed
An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.
- CVSS v3
- 6.1
- EG Score
- 6.1MEDIUMhigh confidence
- EG Risk
- 27EG Risk 27/100
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)Severity61% × 45%The EG Score, 6.1 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 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: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release. - EPSS PROB
- 0.3%
- EPSS %ILE
- 23rd
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.
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.
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
October 12, 2026
Last Modified
October 13, 2026
Advisory Details (5)
Auto-updated Oct 13, 2026Upstream fix merged — awaiting tagged release. Sources: github_pr, github_commit.
Web page
Vercel deepsec before 1.1.17 Arbitrary File Write via Symlink in Sandbox Tarball Extraction | Advisories | VulnCheck
https://www.vulncheck.com/advisories/vercel-deepsec-before-1.1.17-arbitrary-file-write-via-symlink-in-sandbox-tarball-extractionWeb page
GitHub - vercel-labs/deepsec: Deepsec is a security harness for finding vulnerabilities in your codebase powered by coding agents · GitHub
https://github.com/vercel-labs/deepsecGitHub commit
commit c5a4e4220ece (vercel-labs/deepsec)
Fix landed in vercel-labs/deepsec commit c5a4e4220ece — awaiting tagged release
https://github.com/vercel-labs/deepsec/commit/c5a4e4220ece72aee67c2ea21f4340e65f673fc1GitHub pull request
Improve windows compat and make tar usage more robust
Fix merged in vercel-labs/deepsec PR #47 on 2026-05-05 — awaiting tagged release
https://github.com/vercel-labs/deepsec/pull/47GitHub pull request
fix(sandbox): refuse symlink/hardlink members in result tarball extra…
Upstream fix in progress (PR #46 · vercel-labs/deepsec, state=open)
https://github.com/vercel-labs/deepsec/pull/46Vendor Advisories for CVE-2026-109375(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 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.
- 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-10-13 16:30 UTCEG score recompute
- 2026-10-13 16:29 UTCGHSA enrichmentGHSA-cchp-25pr-r776 · GitHub CVSS 6.1
- 2026-10-13 15:57 UTCEG score recompute
- 2026-10-13 15:56 UTCGHSA enrichmentGHSA-cchp-25pr-r776 · GitHub CVSS 6.1
- 2026-10-12 21:29 UTCEG score recompute
- 2026-10-12 21:02 UTCEG score recomputeFirst assessed: 6.1 MEDIUM
- 2026-10-12 20:59 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-109375?
CVE-2026-109375 is a medium-severity vulnerability; its CVE record was published on October 12, 2026. Vercel deepsec from 0.1.0 before 1.1.17 contains a link following vulnerability in extractTarballLocally that allows sandboxed code to write files outside the sandbox by planting links in result tarballs. Attackers controlling sandbox code, such as a prompt-injected coding agent, can plant symbolic…
When was CVE-2026-109375 made public?
CVE-2026-109375 was made public on May 5, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on October 12, 2026. EchelonGraph's copy of the record carries a last-modified date of October 13, 2026; the record at its source may have been updated since.
Is CVE-2026-109375 actively exploited?
CVE-2026-109375 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (23rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-109375?
CVE-2026-109375 has a CVSS base score of 6.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-109375?
An upstream fix for CVE-2026-109375 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-109375 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-109375
Is Your Infrastructure Affected by CVE-2026-109375?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.