CVE-2021-41270
Description
Symfony/Serializer handles serializing and deserializing data structures for Symfony, a PHP framework for web and console applications and a set of reusable PHP components. Symfony versions 4.1.0 before 4.4.35 and versions 5.0.0 before 5.3.12 are vulnerable to CSV injection, also known as formula injection. In Symfony 4.1, maintainers added the opt-in `csv_escape_formulas` option in the `CsvEncoder`, to prefix all cells starting with `=`, `+`, `-` or `@` with a tab `\t`. Since then, OWASP added 2 chars in that list: Tab (0x09) and Carriage return (0x0D). This makes the previous prefix char (Tab `\t`) part of the vulnerable characters, and OWASP suggests using the single quote `'` for prefixing the value. Starting with versions 4.4.34 and 5.3.12, Symfony now follows the OWASP recommendations and uses the single quote `'` to prefix formulas and add the prefix to cells starting by `\t`, `\r` as well as `=`, `+`, `-` and `@`.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 4.4.19+dfsg-3 |
| sid | Fixed | 4.4.19+dfsg-3 |
| forky | Fixed | 4.4.19+dfsg-3 |
| bullseye | Fixed | 4.4.19+dfsg-2+deb11u1 |
| bookworm | Fixed | 4.4.19+dfsg-3 |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| Packagist | symfony/serializer | >=5.0.0,<5.3.12 | 5.3.12 |
| Packagist | symfony/serializer | >=4.1.0,<4.4.35 | 4.4.35 |
| Packagist | symfony/symfony | >=4.1.0,<4.4.35 | 4.4.35 |
| Packagist | symfony/symfony | >=5.0.0,<5.3.12 | 5.3.12 |
References
- https://github.com/symfony/symfony/security/advisories/GHSA-2xhg-w2g5-w95x
- https://nvd.nist.gov/vuln/detail/CVE-2021-41270
- https://github.com/symfony/symfony/pull/44243
- https://github.com/symfony/symfony/commit/3da6f2d45e7536ccb2a26f52fbaf340917e208a8
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/serializer/CVE-2021-41270.yaml
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2021-41270.yaml
- https://github.com/symfony/symfony
- https://github.com/symfony/symfony/releases/tag/v5.3.12
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3BPT4SF6SIXFMZARDWED5T32J7JEH3EP
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QSREFD2TJT5LWKM6S4MD3W26NQQ5WJUP
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3BPT4SF6SIXFMZARDWED5T32J7JEH3EP
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QSREFD2TJT5LWKM6S4MD3W26NQQ5WJUP
- https://symfony.com/cve-2021-41270
- https://security-tracker.debian.org/tracker/CVE-2021-41270
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.