Security Digest · Vulnerability record
CVE-2026-52777: YesWiki Vulnerable to Authenticated PHP Object Injection in BazarImportAction via unserialize
YesWiki is a wiki system written in PHP. Prior to version 4.6.6, there is an authenticated PHP object injection vulnerability in BazarImportAction via unserialize.
CVSS 9.4 Critical EPSS 0.3% · p19
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.3%, percentile 19: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 19% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Only applies if your dependency tree includes
yeswiki/yeswiki(Composer (PHP)) < 4.6.6, fixed in 4.6.6. Check your lockfile, including transitive dependencies.
What it is
YesWiki is a wiki system written in PHP. Prior to version 4.6.6, there is an authenticated PHP object injection vulnerability in BazarImportAction via unserialize. This issue has been patched in version 4.6.6.
From the GitHub advisory
Details
Sink
tools/bazar/services/CSVManager.php line 372-399:
There is no ['allowedclasses' => false] argument; arbitrary classes are instantiated. The subsequent arraymap('strval', $entry) additionally exercises toString on each top-level array element, doubling the magic-method surface available to a gadget chain.
Source
Weakness type: CWE-352, CWE-502.
Product: yeswiki/yeswiki (Composer (PHP)) · Assigned by: GitHub_M · Published: 2026-09-04
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Composer (PHP) | yeswiki/yeswiki | < 4.6.6 | 4.6.6 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| YesWiki | yeswiki | < 4.6.6 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 4.0 | 9.4 Critical | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
| GitHub | 4.0 | 9.4 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: none
- Privileges required: none (no login)
- User interaction: active
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.28% probability of exploitation activity in the next 30 days; percentile 19.
Timeline
- — GitHub-reviewed advisory GHSA-9369-69wj-7m2f published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-9369-69wj-7m2f github.com
- CVE.org record CVE-2026-52777 cve.org
- NVD entry CVE-2026-52777 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
Critical Composer (PHP) advisories · Today’s Security Digest