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 — 3 sources updated this weekElevated
4.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.3Exploit: NoneExposed: 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
24.8%
KEV
Not listed

Published

May 24, 2026

Last Modified

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

Related CVEs(same vendor + same CWE)

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 June 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-9358 actively exploited?
CVE-2026-9358 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 24.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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.

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