major vulnerability· requires attention

Symfony is a widely used web framework; this unauthenticated flaw allows server file read/move across many versions and can impact many web apps and services.

Web

CVE-2026-118515

8.4

High

EPSS n/aPatch available

Symfony Serializer lets attacker treat arbitrary server files as uploads

exploited

No known exploitation not in CISA KEV as of our last sync

fix

Patch available see the advisory in the references

likelihood

No EPSS score yet

Published 6 Nov 2026Analysed here 8 Nov 2026CVSS scored by the publisher (CNA)

common questions

Is CVE-2026-118515 being exploited?

Not confirmed. CVE-2026-118515 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.

How severe is CVE-2026-118515?

CVE-2026-118515 is rated High with a CVSS score of 8.4. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-118515?

Yes. A fix has been recorded for CVE-2026-118515. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-118515 affect?

CVE-2026-118515 affects Symfony < 5.4.56, Symfony 6.x < 6.4.50, Symfony 7.x < 7.4.23, Symfony 8.x < 8.1.11, and 1 further product or version. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-118515?

Upgrade to patched Symfony releases and avoid deserializing untrusted payloads

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary

technical analysis

affected

Symfony < 5.4.56Symfony 6.x < 6.4.50Symfony 7.x < 7.4.23Symfony 8.x < 8.1.11Apps using Serializer + UploadedFile properties (e.g., MapRequestPayload DTOs)

impact

Unauthenticated deserialization of attacker JSON/form lets attacker read any PHP-readable file, move/overwrite files, and detect paths.

action required

Immediate action required

affected versions

sensiolabs symfony

affected< 5.4.56
affected>= 6.0.0 and < 6.4.50
affected>= 7.0.0 and < 7.4.23
affected>= 8.0.0 and < 8.1.11

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

timeline

6 Nov 2026Published
6 Nov 2026CVE record last updated · same day later
8 Nov 2026Analysed by vulneraibility.com · 2 days later

also known as

GHSA-h38r-xrmh-cwhr

how to fix

Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.

references

NVD CVE.org CVE Details Source

3 references in the CVE record: 1 advisory, 2 patches

Advisorygithub.com /symfony/symfony/security/advisories/GHSA-h38r-xrmh-cwhr
Patchgithub.com /symfony/symfony/commit/72ece5bb3084e8233325166357f85c8c0650ee86
Patchgithub.com /symfony/symfony/commit/c459104eb18ebda31e112c5490970da3f30bd668

sources

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
FIRST EPSS: exploit probability and percentile
OSV: advisory aliases and downstream package versions
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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