CVE-2026-18503

LOWPre-NVD 2.42.4—
EchelonGraph scoreMEDIUM confidence

This low-severity CVE scores 2.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 98% 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, secondary
Trending — 4 sources updated this week
2.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 2.4Exploit: None knownExposed: 0

A fix is available — apply it.

Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().

CVSS v3
2.4
EG Score
2.4(medium)
EG Risk
11(Track)
EG Risk 11/100SSVC: 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
Severity24% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

August 10, 2026

Last Modified

August 18, 2026

References (9)

Vendor Advisories for CVE-2026-18503(6)

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

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatpython3-12-main-3.12.14-1.hum12026-08-21redhat
redhatpython3-11-main-3.11.16-1.hum12026-08-20redhat
redhatpython3-10-main-3.10.21-1.hum12026-08-19redhat
redhatpython3-14-main-3.14.7-1.hum12026-08-13redhat
redhatpython3-13-main-3.13.15-1.hum12026-08-13redhat

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

(8 across 3 ecosystems)
Debian:14(4)
PackageVulnerable rangeFixed inDependents
pypy37.3.19+dfsg-2 ... 7.3.23+dfsg-1 (11 versions)——
python3.133.13.11-1 ... 3.13.9-1 (8 versions)3.13.15-1—
python3.143.14.0-1 ... 3.14.6-1 (24 versions)3.14.7-1—
python3.153.15.0~a8-1 ... 3.15.0~b4-1 (8 versions)3.15.0~rc1-1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
pypy37.3.11+dfsg-2 ... 7.3.23+dfsg-1 (29 versions)——
python3.113.11.2-6 ... 3.11.9-1 (28 versions)——
Debian:13(2)
PackageVulnerable rangeFixed inDependents
pypy37.3.19+dfsg-2 ... 7.3.23+dfsg-1 (11 versions)——
python3.133.13.11-1 ... 3.13.9-1 (13 versions)——

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 13× in last 7d / 51× 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. 2026-09-18 19:27 UTCEPSS rescore
  2. 2026-09-18 06:49 UTCEG score recompute
  3. 2026-09-18 06:49 UTCVendor advisory
  4. 2026-09-18 06:49 UTCGHSA enrichment
  5. 2026-09-16 14:07 UTCEPSS rescore
  6. 2026-09-16 05:14 UTCEPSS rescore
  7. 2026-09-15 06:34 UTCEG score recompute
  8. 2026-09-15 06:34 UTCVendor advisory
  9. 2026-09-15 06:34 UTCGHSA enrichment
  10. 2026-09-13 16:46 UTCEPSS rescore
  11. 2026-09-12 06:19 UTCEG score recompute
  12. 2026-09-12 06:19 UTCVendor advisory
  13. 2026-09-12 06:19 UTCGHSA enrichment
  14. 2026-09-11 14:52 UTCEPSS rescore
  15. 2026-09-11 09:36 UTCEPSS rescore
  16. 2026-09-10 09:34 UTCEPSS rescore
  17. 2026-09-09 05:51 UTCEG score recompute
  18. 2026-09-09 05:51 UTCVendor advisory
  19. 2026-09-09 05:51 UTCGHSA enrichment
  20. 2026-09-08 22:00 UTCEPSS rescore
  21. 2026-09-07 16:01 UTCEPSS rescore
  22. 2026-09-06 13:47 UTCEPSS rescore
  23. 2026-09-06 02:46 UTCEG score recompute
  24. 2026-09-06 02:46 UTCVendor advisory
  25. 2026-09-06 02:46 UTCGHSA enrichment
Show 54 more
  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-03 02:31 UTCEG score recompute
  3. 2026-09-03 02:31 UTCVendor advisory
  4. 2026-09-03 02:31 UTCGHSA enrichment
  5. 2026-09-02 14:11 UTCEPSS rescore
  6. 2026-09-01 13:53 UTCEPSS rescore
  7. 2026-09-01 04:39 UTCEPSS rescore
  8. 2026-08-30 20:00 UTCEG score recompute
  9. 2026-08-30 20:00 UTCVendor advisory
  10. 2026-08-30 20:00 UTCGHSA enrichment
  11. 2026-08-30 19:17 UTCEPSS rescore
  12. 2026-08-28 21:41 UTCEPSS rescore
  13. 2026-08-27 19:43 UTCEG score recompute
  14. 2026-08-27 19:43 UTCVendor advisory
  15. 2026-08-27 19:43 UTCGHSA enrichment
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-25 13:48 UTCEPSS rescore
  19. 2026-08-24 17:29 UTCEG score recompute
  20. 2026-08-24 17:29 UTCVendor advisory
  21. 2026-08-24 17:29 UTCGHSA enrichment
  22. 2026-08-21 23:49 UTCEPSS rescore
  23. 2026-08-21 15:48 UTCEG score recompute
  24. 2026-08-21 15:48 UTCVendor advisory
  25. 2026-08-21 15:48 UTCGHSA enrichment
  26. 2026-08-20 22:55 UTCEPSS rescore
  27. 2026-08-19 17:03 UTCEPSS rescore
  28. 2026-08-18 15:33 UTCEG score recompute
  29. 2026-08-18 15:33 UTCGHSA enrichment
  30. 2026-08-18 13:48 UTCEPSS rescore
  31. 2026-08-17 13:47 UTCEPSS rescore
  32. 2026-08-16 14:56 UTCEPSS rescore
  33. 2026-08-16 02:14 UTCEPSS rescore
  34. 2026-08-16 01:38 UTCEG score recompute
  35. 2026-08-16 01:38 UTCGHSA enrichment
  36. 2026-08-15 01:30 UTCEPSS rescore
  37. 2026-08-13 22:00 UTCEPSS rescore
  38. 2026-08-13 01:23 UTCEG score recompute
  39. 2026-08-13 01:23 UTCGHSA enrichment
  40. 2026-08-13 00:41 UTCEG score recompute
  41. 2026-08-13 00:41 UTCGHSA enrichment
  42. 2026-08-12 13:50 UTCEPSS rescore
  43. 2026-08-12 01:20 UTCEG score recompute
  44. 2026-08-12 01:20 UTCGHSA enrichment
  45. 2026-08-12 00:40 UTCEG score recompute
  46. 2026-08-12 00:40 UTCGHSA enrichment
  47. 2026-08-11 13:42 UTCEPSS rescore
  48. 2026-08-10 18:24 UTCEG score recompute
  49. 2026-08-10 18:24 UTCGHSA enrichment
  50. 2026-08-10 18:15 UTCEG score recompute
  51. 2026-08-10 18:15 UTCGHSA enrichment
  52. 2026-08-10 14:29 UTCEG score recompute
  53. 2026-08-10 14:06 UTCEG score recompute
  54. 2026-08-10 14:05 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-18503?
CVE-2026-18503 is a low vulnerability published on August 10, 2026. Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().
When was CVE-2026-18503 disclosed?
CVE-2026-18503 was first published in the National Vulnerability Database on August 10, 2026, with the most recent update on August 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18503 actively exploited?
CVE-2026-18503 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 98.0% of all scored CVEs.
What is the CVSS score of CVE-2026-18503?
CVE-2026-18503 has a CVSS v3 base score of 2.4 (NVD).
How do I remediate CVE-2026-18503?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18503, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-18503

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