---
title: "CVE-2026-52777: YesWiki Vulnerable to Authenticated PHP Object Injection in BazarImportAction via unserialize"
url: https://erroneo.us/security/cve/CVE-2026-52777/
description: "CVE-2026-52777 (yeswiki/yeswiki (Composer (PHP))): YesWiki is a wiki system written in PHP. Prior to version 4.6.6, there is an authenticated PHP object…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-09-04
date_modified: 2026-09-08
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-52777"
kev: false
cvss: 9.4
epss: 0.00276
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-52777: YesWiki Vulnerable to Authenticated PHP Object Injection in BazarImportAction via unserialize

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- 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.

## Affected packages

- Composer (PHP) `yeswiki/yeswiki` < 4.6.6 → fixed: 4.6.6

## Affected products (CVE record)

- YesWiki yeswiki: < 4.6.6

## Severity

- GitHub_M CVSS 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`
- GitHub CVSS 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`

## Exploitation

- 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.

## Sources

- [GitHub Advisory GHSA-9369-69wj-7m2f](https://github.com/advisories/GHSA-9369-69wj-7m2f)
- [CVE.org record CVE-2026-52777](https://www.cve.org/CVERecord?id=CVE-2026-52777)
- [NVD entry CVE-2026-52777](https://nvd.nist.gov/vuln/detail/CVE-2026-52777)
- [github.com](https://github.com/YesWiki/yeswiki/security/advisories/GHSA-9369-69wj-7m2f)
- [github.com](https://github.com/YesWiki/yeswiki/commit/8f70a8d6b8befa0e644d03c785701dbbc55b8fd0)
- [github.com](https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6)

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Source page: https://erroneo.us/security/cve/CVE-2026-52777/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt