In Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9, the parser of the
Affects symfonySource GCVE Database
Not known to be exploited · CVSS 8.7 High.
Data as of 29 Oct 2026, 00:13 UTC
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 15 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10symfonypkg:deb/ubuntu/symfony?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSsymfonypkg:deb/ubuntu/symfony?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu Pro 24.04 LTSsymfonypkg:deb/ubuntu/symfony?arch=source&distro=esm-apps/nobleOther threats | Affected
| Fixed in– |
Ubuntu Pro 22.04 LTSsymfonypkg:deb/ubuntu/symfony?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSsymfonypkg:deb/ubuntu/symfony?arch=source&distro=esm-apps/focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSsymfonypkg:deb/ubuntu/symfony?arch=source&distro=esm-apps/bionicOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade Symfony Expression Language to versions 5.4.54, 6.4.48, 7.4.21, or 8.1.9 or later, where the parser includes bounds on node tree depth to prevent crashes. No other mitigation is indicated. Patch status is confirmed by the presence of fixed versions.
Description
Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9 contain a vulnerability where the parser builds an unbounded depth node tree. This can cause the PHP process to crash when parsing expressions with extremely deep nesting of unary operators, array literals, binary operators, or property accesses. Applications that validate or parse untrusted expressions, such as those using #[Assert\ExpressionSyntax], are susceptible to denial-of-service via a single crafted request.
References
- ubuntu.com/security/CVE-2026-109449 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-109449 (opens in a new tab)
- github.com/symfony/symfony/pull/65690 (opens in a new tab)
- github.com/symfony/symfony/pull/66720 (opens in a new tab)
- github.com/symfony/symfony/pull/66723 (opens in a new tab)
- github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr (opens in a new tab)
- symfony.com/blog/cve-2026-109449-unbounded-nesting-in-the-expression-parser-lets-untrusted-expressions-crash-the-process (opens in a new tab)