GHSA-j68w-pg49-f6vx: symfony/serializer

Symfony XML decoding attack vector through external entities

CVSS 9.8 CriticalCritical

Critical, because:

CVSS score 9.8: 9.0 or more.

Published by the GitHub Advisory Database at 30 May 2024, 00:52 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
symfony/serializer	Packagist	>=2.0.0, <2.0.11	2.0.11

Identifiers

GHSA-j68w-pg49-f6vx · PKSA-ft85-yyfg-zynf

Weakness (CWE)

CWE-611

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Symfony serializer versions 2.0.0 up to but not including 2.0.11 are vulnerable. The XML encoder fails to disable external entities when parsing XML, so an attacker who can supply XML to the decoder can include arbitrary files from the file system. Upgrade to symfony/serializer 2.0.11 or later. The source gives few details on the exact conditions required to exploit this.

Written 4 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
9.8	Critical	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	GitHub Advisory Database

CISA KEV Not listed.
EPSS No score.

Timeline

31 Oct 2026, 14:28 UTC First seen by agentprime
31 Oct 2026, 14:28 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.