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gittuf authorization bypass in file protection rules

CVE-2026-128034

5.5MediumCNA
Exploited
No known exploitation
Fix
Fixed in 0.18.0
Who is exposed
Not reported

Do first: Upgrade to a fixed version: 0.18.0.

Published
Last modified
Reference
Last checked
16/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

gittuf, a Git security tool, has a flaw in how it checks file protection rules: files with special characters in their names (such as non-ASCII characters) are treated as unprotected, so a local user who is not authorized by a rule can change a protected file with such a name and still pass verification. Exploiting it requires only low-privilege local access, and no user interaction is needed.

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

Read the original description

In gittuf before 0.18.0, verification of file protection rules uses the quoted, escaped pathnames that Git prints by default for files with special characters (for example non-ASCII characters) instead of the raw paths. Such paths do not match patterns like file:internal/*, so the files are treated as unprotected, and a user who is not authorized by a file protection rule can change a protected file whose name contains special characters and still pass verification.

cve.now Index

16Pcve.now Index 16 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure?/25Unknown. No advisory context yet
  • Reach10/20Affects Go packages
  • Severity5.5/10CVSS 5.5
  • No patch0/5No signal

What would change the score

  • Would score about 71 if added to CISA KEV
  • Would score about 66 if CISA's SSVC rates exploitation active
  • Would score about 38 if advisories confirm default setups are exposed

What to do

  • Upgrade to a fixed version: 0.18.0.

Check your systems with an agent

Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.

Check whether my systems are affected by CVE-2026-128034 (gittuf: File protection rules bypassed for filenames with special characters), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-128034 (entry last updated 2026-11-13):
Affected:
- Go package github.com/gittuf/gittuf: fixed in 0.18.0
Fixed versions: 0.18.0.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-128034 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-128034 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Packages (Go): find every lockfile in each project and run the stack.check operation of the cve.now MCP server (execute) on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/gittuf/gittuf/security/advisories/GHSA-hxqr-h35w-2898
- https://github.com/gittuf/gittuf/releases/tag/v0.18.0
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-128034
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-128034"}.

Timeline

  1. CVE published
  2. First seen by cve.now

Affected versions

Evidence 4

Vendor advisory · 1

Establishes: Affected and fixed versions.

  1. Advisory

CVE record · 2

Establishes: The identifier and description.

  1. Record
  2. Record

Other links · 1

  1. Repository

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-128034

Is CVE-2026-128034 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by CVE-2026-128034?

github.com/gittuf/gittuf (Go): before 0.18.0.Source: cve.now feed data

How do I fix CVE-2026-128034?

Upgrade to a fixed version: 0.18.0.Source: cve.now feed data