CVE-2021-41270

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.9%, top 25% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.5Exploit: NoneExposed: 0

A fix is available — apply it.

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 @.

CVSS v3
6.5
EG Score
6.5(medium)
EPSS
68.4%
KEV
Not listed

Published

November 24, 2021

Last Modified

November 21, 2024

References (12)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuphp-symfony-console (3.4.6+dfsg-1ubuntu0.1+esm2) @ bionic2026-05-26ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 1 ecosystem)
Packagist(2)
PackageVulnerable rangeFixed inDependents
symfony/serializerv4.1.0 ... v4.4.9 (76 versions)4.4.35—
symfony/symfonyv5.0.0 ... v5.3.9 (64 versions)5.3.12—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 9× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-12 05:44 UTCEPSS rescore
  2. 2026-07-11 08:25 UTCEPSS rescore
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  16. 2026-06-30 23:20 UTCEPSS rescore
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  18. 2026-06-30 04:30 UTCOSV refresh
  19. 2026-06-29 14:04 UTCEPSS rescore
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  1. 2026-06-25 13:48 UTCEPSS rescore
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  10. 2026-06-19 19:24 UTCEPSS rescore
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  22. 2026-06-13 22:58 UTCEPSS rescore
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  24. 2026-06-12 23:10 UTCEPSS rescore
  25. 2026-06-12 16:10 UTCOSV refresh
  26. 2026-06-11 13:58 UTCEPSS rescore
  27. 2026-06-11 13:58 UTCEPSS rescore
  28. 2026-06-10 22:16 UTCEPSS rescore
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  30. 2026-06-10 13:20 UTCEPSS rescore
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  37. 2026-06-05 22:45 UTCEPSS rescore
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  40. 2026-06-04 13:10 UTCEPSS rescore
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  42. 2026-06-02 20:11 UTCEPSS rescore
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  44. 2026-06-01 13:50 UTCEPSS rescore
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  46. 2026-05-31 22:29 UTCEPSS rescore
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  48. 2026-05-31 00:15 UTCEPSS rescore
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  50. 2026-05-29 13:42 UTCEPSS rescore
  51. 2026-05-28 13:43 UTCEPSS rescore
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  53. 2026-05-27 13:39 UTCEPSS rescore
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  55. 2026-05-26 13:42 UTCEPSS rescore
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  57. 2026-05-26 07:17 UTCEPSS rescore
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  59. 2026-05-26 07:17 UTCEPSS rescore
  60. 2026-05-26 07:08 UTCEG score recompute
  61. 2026-05-26 07:08 UTCVendor advisory

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-41270?
CVE-2021-41270 is a medium vulnerability published on November 24, 2021. 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…
When was CVE-2021-41270 disclosed?
CVE-2021-41270 was first published in the National Vulnerability Database on November 24, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-41270 actively exploited?
CVE-2021-41270 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 68.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-41270?
CVE-2021-41270 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2021-41270?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-41270, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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