How severe is GHSA-84f2-rp86-235p?

No CVSS score has been assigned to GHSA-84f2-rp86-235p yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-84f2-rp86-235p?

GHSA-84f2-rp86-235p affects the following packages: cowlib (Hex). Ecosystems affected: Hex.

How do I fix GHSA-84f2-rp86-235p?

Update cowlib to 2.16.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-84f2-rp86-235p is resolved across your whole dependency graph.

How do I detect GHSA-84f2-rp86-235p in my Hex dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cowlib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-84f2-rp86-235p if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-84f2-rp86-235p actively exploited in the wild?

No public exploit code has been indexed for GHSA-84f2-rp86-235p yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-84f2-rp86-235p?

GHSA-84f2-rp86-235p has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 44th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-84f2-rp86-235p?

GHSA-84f2-rp86-235p is classified as CWE-409 (CWE-409). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-84f2-rp86-235p published, and has it been updated?

GHSA-84f2-rp86-235p was published on May 13, 2026 and was last updated on May 19, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💧 Hex

Not in CISA KEV

cowlib: Decompression Bomb in cow_spdy:inflate/2 Allows Memory Exhaustion via Crafted SPDY FrameGHSA-84f2-rp86-235p

Fix: ninenines/cowlib@16aad3f

GHSA-84f2-rp86-235p is a CWE-409 vulnerability in cowlib. A fix is available for cowlib — see the affected versions and patch details below.

Also known asCVE-2026-43970EEF-CVE-2026-43970

Published

May 13, 2026

Updated

May 19, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-84f2-rp86-235p.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs44th percentile — riskier than 44% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

💧cowlib

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💧Hex	`cowlib`	≥ 0.1.0&&< 2.16.1	2.16.1`mix deps.update cowlib`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cowlib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update cowlib to 2.16.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-84f2-rp86-235p is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

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 conditio

O3 Security · Impact-Aware SCA

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