CVE-2026-9358

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

Score 4.3 from GitHub Security Advisory (severity: LOW) published 2026-05-26. a secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this weekElevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: Elevated riskExposed: 0

A fix is available — apply it.

A vulnerability was determined in postcss-selector-parser up to 6.1.2/7.1.2. Affected is the function toString of the file src/selectors/container.js of the component AST Serialization. Executing a manipulation can lead to uncontrolled recursion. It is possible to launch the attack remotely. The exploit has been publicly disclosed and may be utilized. Upgrading to version 6.1.3 and 7.1.3 is able to address this issue. This patch is called 5bc698cef66f8abd12610dc623e5d67cbc0f869d. It is suggested to upgrade the affected component. The vendor explains, that according to his definition "DoS on server-side on user-generated CSS is low risk for us (since most users compile own CSS with PostCSS)." The commits were backported to 6.x branch, which was the most downloaded version.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
25%
KEV
Not listed

Published

May 24, 2026

Last Modified

July 23, 2026

Advisory Details (3)

Auto-updated Jun 15, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release.
github_release Patch Available

7.1.3

Patch available: postcss/postcss-selector-parser 7.1.3

https://github.com/postcss/postcss-selector-parser/releases/tag/7.1.3
github_commit Patch Available

commit 5bc698cef66f (postcss/postcss-selector-parser)

Patch available: postcss/postcss-selector-parser 7.1.3 (contains commit 5bc698cef66f)

https://github.com/postcss/postcss-selector-parser/commit/5bc698cef66f8abd12610dc623e5d67cbc0f869d
generic🟡 PoC Available

Uncontrolled Recursion in AST Serialization (toString) Leads to Stack Overflow DoS · GitHub

https://gist.github.com/bx33661/581e3a38134601c04e19b4dfc9b459b9

Vendor Advisories for CVE-2026-9358(2)

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
redhatrust-main-1.96.0-1.hum12026-06-03redhat

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.

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× 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.

  1. 2026-07-26 14:54 UTCEPSS rescore
  2. 2026-07-26 08:03 UTCEG score recompute
  3. 2026-07-26 08:03 UTCVendor advisory
  4. 2026-07-26 08:03 UTCGHSA enrichment
  5. 2026-07-25 14:18 UTCEPSS rescore
  6. 2026-07-24 14:18 UTCEPSS rescore
  7. 2026-07-23 14:18 UTCEPSS rescore
  8. 2026-07-23 03:23 UTCEG score recompute
  9. 2026-07-22 14:08 UTCEPSS rescore
  10. 2026-07-20 17:08 UTCEPSS rescore
  11. 2026-07-19 14:31 UTCEPSS rescore
  12. 2026-07-19 02:29 UTCEPSS rescore
  13. 2026-07-18 10:04 UTCEPSS rescore
  14. 2026-07-17 04:24 UTCOSV refresh
  15. 2026-07-16 17:03 UTCEPSS rescore
  16. 2026-07-15 16:57 UTCEPSS rescore
  17. 2026-07-15 02:00 UTCEPSS rescore
  18. 2026-07-13 22:31 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-12 05:46 UTCEPSS rescore
  21. 2026-07-11 08:27 UTCEPSS rescore
  22. 2026-07-09 19:10 UTCEPSS rescore
  23. 2026-07-08 15:16 UTCEPSS rescore
  24. 2026-07-06 16:27 UTCEPSS rescore
  25. 2026-07-06 02:23 UTCEPSS rescore
Show 69 more
  1. 2026-07-05 02:31 UTCEPSS rescore
  2. 2026-07-04 06:31 UTCEPSS rescore
  3. 2026-07-04 06:31 UTCEPSS rescore
  4. 2026-07-01 15:07 UTCEPSS rescore
  5. 2026-06-30 23:22 UTCEPSS rescore
  6. 2026-06-29 14:06 UTCEPSS rescore
  7. 2026-06-29 02:47 UTCVendor advisory
  8. 2026-06-29 02:47 UTCGHSA enrichment
  9. 2026-06-28 14:07 UTCEPSS rescore
  10. 2026-06-28 04:56 UTCEPSS rescore
  11. 2026-06-27 21:17 UTCVendor advisory
  12. 2026-06-27 21:17 UTCGHSA enrichment
  13. 2026-06-27 03:08 UTCEPSS rescore
  14. 2026-06-26 19:04 UTCVendor advisory
  15. 2026-06-26 19:04 UTCGHSA enrichment
  16. 2026-06-25 13:50 UTCEPSS rescore
  17. 2026-06-25 13:49 UTCVendor advisory
  18. 2026-06-25 13:49 UTCGHSA enrichment
  19. 2026-06-24 14:05 UTCEPSS rescore
  20. 2026-06-23 21:33 UTCEPSS rescore
  21. 2026-06-22 14:25 UTCEPSS rescore
  22. 2026-06-21 14:56 UTCEPSS rescore
  23. 2026-06-21 01:59 UTCEPSS rescore
  24. 2026-06-19 19:26 UTCEPSS rescore
  25. 2026-06-18 17:52 UTCEPSS rescore
  26. 2026-06-17 17:53 UTCEPSS rescore
  27. 2026-06-17 12:42 UTCGHSA enrichment
  28. 2026-06-16 17:53 UTCEPSS rescore
  29. 2026-06-16 10:30 UTCGHSA enrichment
  30. 2026-06-15 17:49 UTCEPSS rescore
  31. 2026-06-15 17:49 UTCEPSS rescore
  32. 2026-06-15 09:26 UTCNVD updateCVSS v4 → 2.1
  33. 2026-06-15 08:06 UTCGHSA enrichment
  34. 2026-06-14 23:18 UTCEPSS rescore
  35. 2026-06-14 06:00 UTCGHSA enrichment
  36. 2026-06-13 23:00 UTCEPSS rescore
  37. 2026-06-13 03:48 UTCGHSA enrichment
  38. 2026-06-12 23:12 UTCEPSS rescore
  39. 2026-06-12 23:12 UTCEPSS rescore
  40. 2026-06-12 01:41 UTCGHSA enrichment
  41. 2026-06-11 14:00 UTCEPSS rescore
  42. 2026-06-10 23:34 UTCGHSA enrichment
  43. 2026-06-10 22:19 UTCEPSS rescore
  44. 2026-06-10 13:22 UTCEPSS rescore
  45. 2026-06-09 21:27 UTCGHSA enrichment
  46. 2026-06-08 19:16 UTCGHSA enrichment
  47. 2026-06-08 14:17 UTCEPSS rescore
  48. 2026-06-07 15:25 UTCEPSS rescore
  49. 2026-06-07 15:08 UTCGHSA enrichment
  50. 2026-06-06 13:47 UTCEPSS rescore
  51. 2026-06-06 13:02 UTCGHSA enrichment
  52. 2026-06-05 22:47 UTCEPSS rescore
  53. 2026-06-05 10:54 UTCGHSA enrichment
  54. 2026-06-05 06:10 UTCEPSS rescore
  55. 2026-06-04 13:12 UTCEPSS rescore
  56. 2026-06-04 08:48 UTCGHSA enrichment
  57. 2026-06-03 06:41 UTCGHSA enrichment
  58. 2026-06-02 20:13 UTCEPSS rescore
  59. 2026-06-02 04:34 UTCGHSA enrichment
  60. 2026-06-01 13:52 UTCEPSS rescore
  61. 2026-06-01 02:27 UTCGHSA enrichment
  62. 2026-05-31 22:30 UTCEPSS rescore
  63. 2026-05-31 00:16 UTCEPSS rescore
  64. 2026-05-29 13:44 UTCEPSS rescore
  65. 2026-05-28 13:44 UTCEPSS rescore
  66. 2026-05-27 13:40 UTCEPSS rescore
  67. 2026-05-26 13:44 UTCEPSS rescore
  68. 2026-05-26 07:18 UTCEPSS rescore
  69. 2026-05-24 06:17 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-9358?
CVE-2026-9358 is a medium vulnerability published on May 24, 2026. A vulnerability was determined in postcss-selector-parser up to 6.1.2/7.1.2. Affected is the function toString of the file src/selectors/container.js of the component AST Serialization. Executing a manipulation can lead to uncontrolled recursion. It is possible to launch the attack remotely. The…
When was CVE-2026-9358 disclosed?
CVE-2026-9358 was first published in the National Vulnerability Database on May 24, 2026, with the most recent update on July 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-9358 actively exploited?
CVE-2026-9358 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 75.1% of all scored CVEs.
What is the CVSS score of CVE-2026-9358?
CVE-2026-9358 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-9358?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-9358, 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.

Dependency Blast Radius

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