Security readout for executives and security teams
Plain-English summary
CVE-2026-24137 affects sigstore’s legacy TUF client. A malicious TUF repository could cause files to be written outside the intended cache directory, limited by the permissions of the running process. Public Sigstore deployment users are stated to be unaffected. The issue is fixed in sigstore 1.10.4.
Executive priority
Treat as a targeted integrity risk, not a broad emergency. Prioritize developer tooling, CI/CD, and signing-verification environments that use old sigstore or Cosign components, especially where processes have write access to sensitive paths.
Technical view
In sigstore versions 1.10.3 and below, pkg/tuf/client.go joins a cache base directory with a target name from signed TUF metadata without ensuring the final path remains inside the cache. This CWE-22 path traversal can overwrite arbitrary files when the legacy client caches targets to disk.
Likely exposure
Exposure is mainly clients directly using sigstore/sigstore’s legacy TUF client or older Cosign versions. Systems using public Sigstore deployment metadata are described as unaffected because metadata is validated by a quorum of trusted collaborators.
Exploitation context
The source states exploitation requires a malicious TUF repository and file overwrite is limited to the calling process’s permissions. CVSS indicates network reachability, high attack complexity, high privileges, no user interaction, and high integrity impact. No active exploitation is reported in the provided sources.
Researcher notes
The advisory’s scope is narrow: legacy sigstore TUF client caching target files. The key control is path containment during cache writes. Public Sigstore deployments are excluded by the source. Evidence does not include proof of exploitation, affected Cosign version ranges, or detailed downstream package mapping.
Mitigation direction
- Upgrade sigstore/sigstore to version 1.10.4 or later.
- Set SIGSTORE_NO_CACHE=true to disable disk caching for the legacy client.
- Migrate to the sigstore-go TUF client referenced by the advisory.
- Check Sigstore and Cosign guidance for older Cosign exposure and upgrade direction.
Validation and detection
- Inventory applications and tools importing sigstore/sigstore legacy TUF client code.
- Confirm sigstore/sigstore dependency versions are 1.10.4 or later.
- Identify older Cosign usage and compare against vendor guidance.
- Verify whether legacy TUF disk caching is enabled in affected environments.
- Confirm workloads do not use untrusted or private maliciously controlled TUF repositories.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-22: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-24137 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N1.34Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.8MediumVector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/sigstore/sigstore/security/advisories/GHSA-fcv2-xgw5-pqxfCVE reference · x_refsource_CONFIRM
- https://github.com/sigstore/sigstore/commit/8ec410a2993ea78083aecf0e473a85453039496eCVE reference · x_refsource_MISC
- https://github.com/sigstore/sigstore/releases/tag/v1.10.4CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.