CVE
gittuf authorization bypass in policy update verification
- Exploited
- No known exploitation
- Fix
- Fixed in 0.17.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 0.17.0.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 12/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
gittuf, a tool for securing Git repositories, has a flaw in how it verifies policy updates: when a policy change falls within the range of reference state log entries being checked, only the root of trust signatures on the new policy are verified, not the signatures on its other metadata such as rule files. A local user who has high privileges and bypasses the gittuf policy apply workflow to write the policy reference and reference state log directly can get an invalid policy accepted during verification, which can weaken or strengthen the rules applied to later changes.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
In gittuf 0.4.0 through 0.16.0, when a policy update appears within the range of reference state log entries being verified, verification checks only the root of trust signatures of the new policy and not the signatures of its other metadata (rule files). A user trusted to push to the repository who bypasses gittuf policy apply and writes the policy reference and reference state log directly can make an invalid policy apply during verification, weakening or strengthening the rules for later changes. The update is still recorded in the reference state log.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach10/20Affects Go packages
- Severity2.3/10CVSS 2.3
- No patch0/5No signal
What would change the score
- Would score about 67 if added to CISA KEV
- Would score about 62 if CISA's SSVC rates exploitation active
- Would score about 34 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 0.17.0.
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-2026-128036 (gittuf: Invalid intermediate policies trusted when the policy apply workflow is bypassed), 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-2026-128036 (entry last updated 2026-11-13):
Affected:
- Go package github.com/gittuf/gittuf: from 0.4.0, fixed in 0.17.0
Fixed versions: 0.17.0.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-128036 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-128036 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-774m-m728-236h
- https://github.com/gittuf/gittuf/releases/tag/v0.17.0
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-2026-128036
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-2026-128036"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
From 0.4.0 · fixed in 0.17.0
Evidence 4
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 1
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-128036
Is CVE-2026-128036 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-2026-128036?
github.com/gittuf/gittuf (Go): from 0.4.0 before 0.17.0.Source: cve.now feed data
How do I fix CVE-2026-128036?
Upgrade to a fixed version: 0.17.0.Source: cve.now feed data