CVE-2026-40261

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 87% 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
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 8.8Exploit: NoneExposed: 0

A fix is available — apply it.

Composer is a dependency manager for PHP. Versions 1.0 through 2.2.26 and 2.3 through 2.9.5 contain a command injection vulnerability in the Perforce::syncCodeBase() method, which appends the $sourceReference parameter to a shell command without proper escaping, and additionally in the Perforce::generateP4Command() method as in GHSA-wg36-wvj6-r67p / CVE-2026-40176, which interpolates user-supplied Perforce connection parameters (port, user, client) from the source url field without proper escaping. An attacker can inject arbitrary commands through crafted source reference or source url values containing shell metacharacters, even if Perforce is not installed. Unlike CVE-2026-40176, the source reference and url are provided as part of package metadata, meaning any compromised or malicious Composer repository can serve package metadata declaring perforce as a source type with malicious values. This vulnerability is exploitable when installing or updating dependencies from source, including the default behavior when installing dev-prefixed versions. This issue has been fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline). If developers are unable to immediately update, they can avoid installing dependencies from source by using --prefer-dist or the preferred-install: dist config setting, and only use trusted Composer repositories as a workaround.

CVSS v3
8.8
EG Score
8.8(medium)
EPSS
74.4%
KEV
Not listed

Published

April 15, 2026

Last Modified

July 15, 2026

Advisory Details (2)

Auto-updated May 2, 2026
Patch available. Sources: github.
github Patch Available

Command injection via malicious Perforce source reference/url · Advisory · composer/composer · GitHub

https://github.com/composer/composer/security/advisories/GHSA-gqw4-4w2p-838q
generic

Release 2.9.6 · composer/composer · GitHub

https://github.com/composer/composer/releases/tag/2.9.6

Vendor Advisories for CVE-2026-40261(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatcomposer-main-2.9.7-1.hum12026-04-14redhat

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

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
composer/composer1.0.0 ... 2.2.9 (146 versions)2.2.27—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 37× 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.

Showing the most recent 100 of 109 total refreshes for this CVE.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 02:00 UTCEPSS rescore
  4. 2026-07-13 22:30 UTCEPSS rescore
  5. 2026-07-13 06:13 UTCEPSS rescore
  6. 2026-07-13 06:13 UTCEPSS rescore
  7. 2026-07-12 05:46 UTCEPSS rescore
  8. 2026-07-11 08:27 UTCEPSS rescore
  9. 2026-07-09 19:10 UTCEPSS rescore
  10. 2026-07-08 15:15 UTCEPSS rescore
  11. 2026-07-07 13:46 UTCEPSS rescore
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-06 16:27 UTCEPSS rescore
  14. 2026-07-06 02:23 UTCEPSS rescore
  15. 2026-07-06 02:23 UTCEPSS rescore
  16. 2026-07-05 02:30 UTCEPSS rescore
  17. 2026-07-04 06:31 UTCEPSS rescore
  18. 2026-07-01 15:06 UTCEPSS rescore
  19. 2026-06-30 23:22 UTCEPSS rescore
  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-28 14:07 UTCEPSS rescore
  22. 2026-06-28 04:56 UTCEPSS rescore
  23. 2026-06-27 03:08 UTCEPSS rescore
  24. 2026-06-25 13:49 UTCEPSS rescore
  25. 2026-06-25 13:49 UTCEPSS rescore
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  1. 2026-06-24 14:05 UTCEPSS rescore
  2. 2026-06-23 21:33 UTCEPSS rescore
  3. 2026-06-22 14:25 UTCEPSS rescore
  4. 2026-06-22 14:25 UTCEPSS rescore
  5. 2026-06-21 14:56 UTCEPSS rescore
  6. 2026-06-21 14:56 UTCEPSS rescore
  7. 2026-06-21 01:59 UTCEPSS rescore
  8. 2026-06-19 19:25 UTCEPSS rescore
  9. 2026-06-18 17:52 UTCEPSS rescore
  10. 2026-06-18 17:52 UTCEPSS rescore
  11. 2026-06-17 17:53 UTCEPSS rescore
  12. 2026-06-16 17:52 UTCEPSS rescore
  13. 2026-06-15 17:49 UTCEPSS rescore
  14. 2026-06-14 20:40 UTCEG score recompute
  15. 2026-06-14 20:40 UTCVendor advisory
  16. 2026-06-13 23:00 UTCEPSS rescore
  17. 2026-06-12 23:12 UTCEPSS rescore
  18. 2026-06-12 23:12 UTCEPSS rescore
  19. 2026-06-12 06:24 UTCEG score recompute
  20. 2026-06-12 06:24 UTCVendor advisory
  21. 2026-06-11 18:58 UTCEG score recompute
  22. 2026-06-11 18:58 UTCVendor advisory
  23. 2026-06-11 14:00 UTCEPSS rescore
  24. 2026-06-10 23:11 UTCEG score recompute
  25. 2026-06-10 23:11 UTCVendor advisory
  26. 2026-06-10 22:18 UTCEPSS rescore
  27. 2026-06-10 13:22 UTCEPSS rescore
  28. 2026-06-10 13:22 UTCEPSS rescore
  29. 2026-06-10 11:47 UTCEG score recompute
  30. 2026-06-10 11:47 UTCVendor advisory
  31. 2026-06-10 00:24 UTCEG score recompute
  32. 2026-06-10 00:24 UTCVendor advisory
  33. 2026-06-09 10:10 UTCEG score recompute
  34. 2026-06-09 10:10 UTCVendor advisory
  35. 2026-06-08 14:17 UTCEPSS rescore
  36. 2026-06-08 14:17 UTCEPSS rescore
  37. 2026-06-08 03:52 UTCEG score recompute
  38. 2026-06-08 03:52 UTCVendor advisory
  39. 2026-06-07 16:29 UTCEG score recompute
  40. 2026-06-07 16:29 UTCVendor advisory
  41. 2026-06-07 15:25 UTCEPSS rescore
  42. 2026-06-07 15:25 UTCEPSS rescore
  43. 2026-06-07 05:06 UTCEG score recompute
  44. 2026-06-07 05:06 UTCVendor advisory
  45. 2026-06-06 13:47 UTCEPSS rescore
  46. 2026-06-06 13:47 UTCEPSS rescore
  47. 2026-06-05 22:47 UTCEPSS rescore
  48. 2026-06-05 06:10 UTCEPSS rescore
  49. 2026-06-05 06:10 UTCEPSS rescore
  50. 2026-06-04 13:12 UTCEPSS rescore
  51. 2026-06-04 13:12 UTCEPSS rescore
  52. 2026-06-03 18:52 UTCEG score recompute
  53. 2026-06-03 18:52 UTCVendor advisory
  54. 2026-06-02 20:13 UTCEPSS rescore
  55. 2026-06-02 14:25 UTCEG score recompute
  56. 2026-06-02 14:25 UTCVendor advisory
  57. 2026-06-01 18:29 UTCEG score recompute
  58. 2026-06-01 18:29 UTCVendor advisory
  59. 2026-06-01 13:52 UTCEPSS rescore
  60. 2026-06-01 13:52 UTCEPSS rescore
  61. 2026-06-01 13:51 UTCEPSS rescore
  62. 2026-05-31 22:30 UTCEPSS rescore
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  64. 2026-05-31 00:16 UTCEPSS rescore
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  66. 2026-05-31 00:16 UTCEPSS rescore
  67. 2026-05-29 13:44 UTCEPSS rescore
  68. 2026-05-29 13:44 UTCEPSS rescore
  69. 2026-05-28 13:44 UTCEPSS rescore
  70. 2026-05-28 13:44 UTCEPSS rescore
  71. 2026-05-28 13:44 UTCEPSS rescore
  72. 2026-05-27 13:40 UTCEPSS rescore
  73. 2026-05-27 13:40 UTCEPSS rescore
  74. 2026-05-27 13:40 UTCEPSS rescore
  75. 2026-05-26 13:44 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-40261?
CVE-2026-40261 is a high vulnerability published on April 15, 2026. Composer is a dependency manager for PHP. Versions 1.0 through 2.2.26 and 2.3 through 2.9.5 contain a command injection vulnerability in the Perforce::syncCodeBase() method, which appends the $sourceReference parameter to a shell command without proper escaping, and additionally in the…
When was CVE-2026-40261 disclosed?
CVE-2026-40261 was first published in the National Vulnerability Database on April 15, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40261 actively exploited?
CVE-2026-40261 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 74.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40261?
CVE-2026-40261 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-40261?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40261, 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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