How severe is CVE-2026-104991?

No CVSS score has been assigned to CVE-2026-104991 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-104991?

Affected package information for CVE-2026-104991 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-104991?

Upgrade the affected component to the fixed release for CVE-2026-104991, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.

How do I detect CVE-2026-104991 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2026-104991 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-104991 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-104991 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-104991?

CVE-2026-104991 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 11th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-104991?

CVE-2026-104991 is classified as CWE-862 (CWE-862). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-104991 published, and has it been updated?

CVE-2026-104991 was published on October 2, 2026 and was last updated on October 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-104991: phproject

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-104991.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs11th percentile — riskier than 11% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Description

Phproject before 1.8.7 contains a missing object-level authorization vulnerability in the REST API issue endpoints (single_get, single_comments, single_comments_post) that allows authenticated API key holders to bypass the security.restrict_access confidentiality control by never invoking the allowAccess() authorization routine. Attackers can use a valid API key to read restricted issue contents and comments, including owner and author email addresses, and post unauthorized comments to issues they should not have access to.

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Fix
Upgrade the affected component to the fixed release for CVE-2026-104991, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

Phproject before 1.8.7 contains a missing object-level authorization vulnerability in the REST API issue endpoints (single_get, single_comments, single_comments_post) that allows authenticated API key holders to bypass the security.restrict_access confidentiality control by never invoking the allowAccess() authorization routine. Attackers can use a valid API key to read restricted issue contents and comments, including owner and author email addresses, and post unauthorized comments to issues they should not have access to.

O3 Security · Impact-Aware SCA

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CVE-2026-104991 — phproject