symfony/routing security advisory

CVE-2026-48784: UrlGenerator Dot-Segment Encoding Skips Every Other Chained ../ or ./ → Generated URL Collapses Off-Route Under RFC 3986 Normalization in symfony/routing

CVE-2026-48784 is a medium-severity open redirect vulnerability in the PHP package symfony/routing (CVSS 6.1), published 14 July 2026. It is fixed in 5.4.53, 6.4.41, 7.4.13 and 8.0.13, one per release line; earlier versions on each line are affected. It can be exploited without an account.

medium 6.1 published 2026-07-14 · updated 2026-07-15

Affected versions: >= 2.0.0, < 5.4.53
>= 6.0.0, < 6.4.41
>= 7.0.0, < 7.4.13
>= 8.0.0, < 8.0.13
Fixed in: 5.4.53, 6.4.41, 7.4.13, 8.0.13
Newest release: 8.1.10
Severity: Medium · CVSS 6.1
Type: Open redirect
CWE-172, CWE-601
Exploited in the wild: Not on the CISA KEV list
checked 2026-11-04

Also affects

The same advisory covers another package in our list. Fix whichever one your project installs.

symfony/symfony >= 2.0.0, < 5.4.53; >= 6.0.0, < 6.4.41; >= 7.0.0, < 7.4.13; >= 8.0.0, < 8.0.13 fixed in 5.4.53, 6.4.41, 7.4.13, 8.0.13

Is your symfony/routing version affected?

Run composer show symfony/routing in your project, then enter the version. We check it against this and every other known symfony/routing advisory.

Who can exploit CVE-2026-48784

Access: No account. Anyone who can send a request to an app that uses the affected code.
Interaction: A user also has to do something, such as open a link or a page the attacker prepared.

CVSS vector (scored by NVD): CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Your app is only exposed if it uses the affected part of symfony/routing. The advisory below says which part that is. If you are not sure, upgrade anyway: it costs less than finding out.

How to fix CVE-2026-48784 in symfony/routing

Find the installed version: composer show symfony/routing. If you never required it yourself, composer why symfony/routing shows which package pulls it in.
Update it: composer update symfony/routing --with-all-dependencies. You need the fixed version for your release line (5.4.53, 6.4.41, 7.4.13 and 8.0.13).
If Composer will not go that high, your composer.json constraint is holding it back. Widen it (for example "symfony/routing": "^8.0.13" if you can take that version), or upgrade the package that requires it.
Run composer audit. It reads the same advisory data and should no longer list CVE-2026-48784.
Commit composer.lock and deploy it. On the server, run composer install --no-dev from the lock file, not composer update.

If you cannot upgrade yet

General hardening for open redirect issues while the upgrade waits. None of it replaces the fix.

Only redirect to relative paths or to an allow-list of your own hosts.
If your app does not use the affected feature, note that in your audit, but still plan the upgrade.

The CVE-2026-48784 advisory

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.53, 6.4.41, 7.4.13, and 8.0.13, UrlGenerator::doGenerate() used strtr() dot-segment encoding that skipped every other chained ../ or ./ segment, allowing attacker-controlled route parameters to generate URLs that collapse to a different path under RFC 3986 normalization. This issue is fixed in versions 5.4.53, 6.4.41, 7.4.13, and 8.0.13.

Description from the CVE record, published by GitHub (the CVE Numbering Authority), via the NVD entry for CVE-2026-48784. Advisory title: “CVE-2026-48784: UrlGenerator Dot-Segment Encoding Skips Every Other Chained ../ or ./ → Generated URL Collapses Off-Route Under RFC 3986 Normalization”.

References

GitHub security advisory GHSA-h5x3-xfc9-m39h github.com
Symfony security advisory symfony.com
Fix commit 4b63c3a github.com
Release v5.4.53 github.com
Release v6.4.41 github.com
Release v7.4.13 github.com

Other symfony/routing advisories

medium CVE-2026-45065: UrlGenerator Route-Requirement Bypass via Unanchored Regex Alternation → Off-Site //host URL Injection 2026-05-20
high Security fixes related to the way XML is handled 2012-08-28
medium CVE-2012-6431: Routes behind a firewall are accessible even when not logged in 2012-03-19

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Where this data comes from

Affected and fixed versions: the Packagist security advisories API (GitHub Advisory Database and FriendsOfPHP), the same data composer audit uses. Synced 2026-11-03.
Description, score, weakness and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
Exploited-in-the-wild status: the CISA Known Exploited Vulnerabilities catalog, checked 2026-11-04.
Compiled by Daniel Lasek at Laskyr from the sources above. The summary, “who can exploit it”, “how to fix it” and hardening sections are our plain-English reading of the record and are generated from it. The quoted description is the record's own text. Spot an error? Tell us.