Is CVE-2026-43970 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-43970 being exploited in the wild.

How severe is CVE-2026-43970?

High severity, with a CVSS score of 8.2, published 13 May 2026.

Which products and versions are affected?

Nine Nines Cowlib >= 0.1.0, < 2.16.1, 0.1.0 before 2.16.1.

Is there a fix for CVE-2026-43970?

A patch was published on 2026-05-19: GitHub advisory reviewed and updated with patch details Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-43970 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-43970?

Check whether you run Nine Nines Cowlib at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-43970: ninenines cowlib denial of service via SPDY decompression bomb

Q: Is there a fix for CVE-2026-43970?

A patch was published on 2026-05-19: GitHub advisory reviewed and updated with patch details Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-43970 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-43970?

Check whether you run Nine Nines Cowlib at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-43970 · Severity: high · CVSS 8.2 · Published 2026-05-13

A vulnerability in the cowlib Erlang library allows an attacker to crash a server by sending a specially crafted SPDY data frame. This library is used for manipulating web protocols, and the flaw can lead to a complete service outage by exhausting the server's memory. Organizations using this library in applications that process SPDY traffic are at risk of a remote denial-of-service attack.

Technologies: Nine Nines Cowlib. Vendors: Nine Nines.

Quick answers

Is CVE-2026-43970 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-43970 being exploited in the wild.
How severe is CVE-2026-43970?: High severity, with a CVSS score of 8.2, published 13 May 2026.
Which products and versions are affected?: Nine Nines Cowlib >= 0.1.0, < 2.16.1, 0.1.0 before 2.16.1.
Is there a fix for CVE-2026-43970?: A patch was published on 2026-05-19: GitHub advisory reviewed and updated with patch details Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-43970 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-43970?: Check whether you run Nine Nines Cowlib at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The cow_spdy:inflate/2 function in cowlib fails to implement output size bounds when passing peer-supplied compressed bytes to zlib:inflate/2. Because the SPDY header compression dictionary is public, an attacker can craft a small SPDY frame (a few kilobytes) that expands to several gigabytes on the BEAM heap, leading to an Out-Of-Memory (OOM) termination of the node. The vulnerability affects the parsers for syn_stream, syn_reply, and headers frame types via cow_spdy:parse_headers/2. The issue was resolved in version 2.16.1 by completely removing the deprecated cow_spdy module.

Affected products

ninenines cowlib >= 0.1.0, < 2.16.1

Identifiers

CVE-2026-43970
GHSA-84f2-rp86-235p

Timeline

2026-05-13: advisory: Initial publication of GHSA-84f2-rp86-235p
2026-05-13: disclosed: CVE-2026-43970 published
2026-05-19: patched: GitHub advisory reviewed and updated with patch details

References

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