CVE-2026-43970

HIGHNVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 60% 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
8.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 8.2Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in ninenines cowlib allows unauthenticated remote denial of service via memory exhaustion.

cow_spdy:inflate/2 in cowlib passes peer-supplied compressed bytes directly to zlib:inflate/2 with no output size bound. The SPDY header compression dictionary (?ZDICT) is public, and zlib compresses long runs of repeated bytes at roughly 1024:1, so a few kilobytes of SPDY frame payload can decompress to gigabytes on the BEAM heap, OOM-killing the node. A single unauthenticated SPDY frame is sufficient to trigger the condition. The parsers for syn_stream, syn_reply, and headers frame types are all affected via cow_spdy:parse_headers/2.

This issue affects cowlib from 0.1.0 before 2.16.1.

CVSS v3
8.2
EG Score
8.2(medium)
EPSS
40.1%
KEV
Not listed

Published

May 13, 2026

Last Modified

May 14, 2026

Advisory Details (3)

Auto-updated May 13, 2026
No patch confirmed yet.
generic

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/EEF-CVE-2026-43970
generic

Remove unused cow_spdy module · ninenines/cowlib@16aad3f · GitHub

https://github.com/ninenines/cowlib/commit/16aad3fb9f81f5cda4d1706ff0c54237c619c282
generic

Decompression Bomb in cow_spdy:inflate/2 Allows Memory Exhaustion via Crafted SPDY Frame | Erlang Ecosystem Foundation CNA

https://cna.erlef.org/cves/CVE-2026-43970.html

Vendor Advisories for CVE-2026-43970(2)

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

Affected Packages

(1 across 1 ecosystem)
Hex(1)
PackageVulnerable rangeFixed inDependents
cowlib1.0.0 ... 2.9.1 (32 versions)2.16.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 40× 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. 2026-07-16 17:03 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
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  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-08 15:16 UTCEPSS rescore
  10. 2026-07-07 13:46 UTCEPSS rescore
  11. 2026-07-06 16:27 UTCEPSS rescore
  12. 2026-07-06 02:23 UTCEPSS rescore
  13. 2026-07-05 02:30 UTCEPSS rescore
  14. 2026-07-04 06:31 UTCEPSS rescore
  15. 2026-07-01 15:07 UTCEPSS rescore
  16. 2026-06-30 23:22 UTCEPSS rescore
  17. 2026-06-29 22:12 UTCEG score recompute
  18. 2026-06-29 14:06 UTCEPSS rescore
  19. 2026-06-28 14:07 UTCEPSS rescore
  20. 2026-06-28 11:26 UTCEG score recompute
  21. 2026-06-28 04:56 UTCEPSS rescore
  22. 2026-06-27 23:22 UTCEG score recompute
  23. 2026-06-27 08:09 UTCEG score recompute
  24. 2026-06-27 03:08 UTCEPSS rescore
  25. 2026-06-26 20:28 UTCEG score recompute
Show 52 more
  1. 2026-06-25 19:35 UTCEG score recompute
  2. 2026-06-25 13:49 UTCEPSS rescore
  3. 2026-06-25 13:49 UTCEPSS rescore
  4. 2026-06-24 14:05 UTCEPSS rescore
  5. 2026-06-23 21:33 UTCEPSS rescore
  6. 2026-06-22 14:25 UTCEPSS rescore
  7. 2026-06-22 14:25 UTCEPSS rescore
  8. 2026-06-21 14:56 UTCEPSS rescore
  9. 2026-06-21 14:56 UTCEPSS rescore
  10. 2026-06-21 01:59 UTCEPSS rescore
  11. 2026-06-19 19:25 UTCEPSS rescore
  12. 2026-06-18 17:52 UTCEPSS rescore
  13. 2026-06-18 17:52 UTCEPSS rescore
  14. 2026-06-17 17:53 UTCEPSS rescore
  15. 2026-06-17 14:26 UTCEG score recompute
  16. 2026-06-16 22:31 UTCEG score recompute
  17. 2026-06-16 17:52 UTCEPSS rescore
  18. 2026-06-15 17:49 UTCEPSS rescore
  19. 2026-06-13 23:00 UTCEPSS rescore
  20. 2026-06-12 23:12 UTCEPSS rescore
  21. 2026-06-12 23:12 UTCEPSS rescore
  22. 2026-06-11 14:00 UTCEPSS rescore
  23. 2026-06-10 22:18 UTCEPSS rescore
  24. 2026-06-10 13:22 UTCEPSS rescore
  25. 2026-06-10 13:22 UTCEPSS rescore
  26. 2026-06-08 14:17 UTCEPSS rescore
  27. 2026-06-08 14:17 UTCEPSS rescore
  28. 2026-06-07 15:25 UTCEPSS rescore
  29. 2026-06-07 15:25 UTCEPSS rescore
  30. 2026-06-06 13:47 UTCEPSS rescore
  31. 2026-06-06 13:47 UTCEPSS rescore
  32. 2026-06-05 22:47 UTCEPSS rescore
  33. 2026-06-05 06:10 UTCEPSS rescore
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  35. 2026-06-04 13:12 UTCEPSS rescore
  36. 2026-06-04 13:12 UTCEPSS rescore
  37. 2026-06-02 20:13 UTCEPSS rescore
  38. 2026-06-01 13:52 UTCEPSS rescore
  39. 2026-06-01 13:52 UTCEPSS rescore
  40. 2026-05-31 22:30 UTCEPSS rescore
  41. 2026-05-31 22:30 UTCEPSS rescore
  42. 2026-05-29 13:44 UTCEPSS rescore
  43. 2026-05-29 13:44 UTCEPSS rescore
  44. 2026-05-28 13:44 UTCEPSS rescore
  45. 2026-05-28 13:44 UTCEPSS rescore
  46. 2026-05-27 13:40 UTCEPSS rescore
  47. 2026-05-27 13:40 UTCEPSS rescore
  48. 2026-05-26 13:44 UTCEPSS rescore
  49. 2026-05-26 07:18 UTCEPSS rescore
  50. 2026-05-20 22:38 UTCEPSS rescore
  51. 2026-05-20 12:25 UTCEG score recompute
  52. 2026-05-20 11:22 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-43970?
CVE-2026-43970 is a high vulnerability published on May 13, 2026. Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in ninenines cowlib allows unauthenticated remote denial of service via memory exhaustion. cowspdy:inflate/2 in cowlib passes peer-supplied compressed bytes directly to zlib:inflate/2 with no output size bound. The SPDY…
When was CVE-2026-43970 disclosed?
CVE-2026-43970 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on May 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43970 actively exploited?
CVE-2026-43970 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 40.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-43970?
CVE-2026-43970 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-43970?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43970, 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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