Is CVE-2026-43970 in the CISA KEV catalog?

No. CVE-2026-43970 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the EPSS score for CVE-2026-43970?

CVE-2026-43970 has an EPSS score of 0.51% (40th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-43970?

Upgrade erlang-cowlib on debian unstable to 2.17.1-1 or later.

CVE & CISA-KEV Catalog

CVE-2026-43970

UNSCORED

NVD

Description

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.

CWE-409

How to fix

Remediation Available

erlang-cowlibDebian

Fixed in:2.17.1-1CVE-2026-43970

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3.1 Vector

No CVSS vector data available.

Exploit Intelligence

0.51%probability of exploitation in 30 days

40thpercentile

Low risk: more likely to be exploited than 40% of all known CVEs.

References

Other references3

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-14.