CVE-2026-118515: sensiolabs symfony · External Control of File Name or Path
Affects sensiolabs symfonySource CVE Database V5
Not known to be exploited · CVSS 8.4 High · fixed in 8.1.11 : patch sensiolabs symfony soon.
Data as of 6 Nov 2026, 17:47 UTC
Thin evidence
One scorer or none| CNA (Checkmarx) | CVSS 4.0 | 8.4 |
|---|
- Patch
- Available – fixed in 8.1.11, 7.4.23, 6.4.50 +1
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 6 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.
What to do
Upgrade symfony and symfony/serializer to 8.1.11, 7.4.23, 6.4.50 or 5.4.56.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| symfonysymfony/serializer | Affected
| Fixed in
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| symfonysymfony/serializer | Affected
| Fixed in
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| symfonysymfony/serializer | Affected
| Fixed in
|
| symfonysymfony/serializer | Affected
| Fixed in
|
Packagistsymfony/serializerpkg:composer/symfony/serializerOther 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 to versions 5.4.56, 6.4.50, 7.4.23, or 8.1.11 or later where this vulnerability is fixed. Ensure that the serializer is configured with DataUriNormalizer ahead of ObjectNormalizer as per the vendor fix. If upgrading is not immediately possible, review deserialization of untrusted data into types with UploadedFile properties and avoid accepting such data from untrusted sources. No other vendor advisory mitigation or no-action statements are provided.
Description
CVE-2026-118515 is a high-severity vulnerability in the Symfony Serializer component affecting versions prior to 5.4.56, 6.4.50, 7.4.23, and 8.1.11. It allows an attacker to craft a request that causes the application to treat arbitrary files on the server as uploaded files without actual upload, potentially exposing or moving sensitive files. This occurs because the DataUriNormalizer only handles specific types, and subclasses like UploadedFile can be instantiated with attacker-controlled paths, bypassing normal upload checks.