CVE-2026-43970
Decompression Bomb in cow_spdy:inflate/2 Allows Memory Exhaustion via Crafted SPDY Frame
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.
INFO
Published Date :
May 13, 2026, 7:17 p.m.
Last Modified :
Oct. 26, 2026, 5:10 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update cowlib to version 2.16.1 or later.
- Apply relevant patches to cowlib.
- Monitor system memory usage.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-43970.
| URL | Resource |
|---|---|
| https://cna.erlef.org/cves/CVE-2026-43970.html | |
| https://github.com/ninenines/cowlib/commit/16aad3fb9f81f5cda4d1706ff0c54237c619c282 | |
| https://osv.dev/vulnerability/EEF-CVE-2026-43970 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-43970 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-43970
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-43970 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-43970 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: cowlib de ninenines, Description: La vulnerabilidad de Manejo Inadecuado de Datos Altamente Comprimidos (Amplificación de Datos) en ninenines cowlib permite una denegación de servicio remota no autenticada a través del agotamiento de la memoria. cow_spdy:inflate/2 en cowlib pasa los bytes comprimidos suministrados por el par directamente a zlib:inflate/2 sin un límite de tamaño de salida. El diccionario de compresión de cabeceras SPDY (?ZDICT) es público, y zlib comprime largas secuencias de bytes repetidos a una proporción aproximada de 1024:1, por lo que unos pocos kilobytes de carga útil de trama SPDY pueden descomprimirse a gigabytes en el heap de BEAM, provocando la terminación del nodo por falta de memoria. Una única trama SPDY no autenticada es suficiente para activar la condición. Los analizadores para los tipos de trama syn_stream, syn_reply y headers están todos afectados a través de cow_spdy:parse_headers/2. Este problema afecta a cowlib desde la versión 0.1.0 anterior a la 2.16.1. -
CVE Modified by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:2.3:a:ninenines:cowlib:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/ninenines/cowlib', 'vendor': 'ninenines', 'modules': ['cow_spdy'], 'product': 'cowlib', 'versions': [{'status': 'affected', 'version': '0.1.0', 'lessThan': '2.16.1', 'versionType': 'semver'}], 'packageURL': 'pkg:hex/cowlib', 'packageName': 'cowlib', 'programFiles': ['src/cow_spdy.erl'], 'collectionURL': 'https://repo.hex.pm', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'cow_spdy:parse/2'}, {'name': 'cow_spdy:inflate/2'}, {'name': 'cow_spdy:parse_headers/2'}, {'name': 'cow_spdy:parse_headers/4'}]}, {'cpes': ['cpe:2.3:a:ninenines:cowlib:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/ninenines/cowlib', 'vendor': 'ninenines', 'modules': ['cow_spdy'], 'product': 'cowlib', 'versions': [{'status': 'affected', 'version': 'fad5c0049df278cc498b6cdb519b09e845a070a8', 'lessThan': '16aad3fb9f81f5cda4d1706ff0c54237c619c282', 'versionType': 'git'}], 'packageURL': 'pkg:github/ninenines/cowlib', 'packageName': 'ninenines/cowlib', 'programFiles': ['src/cow_spdy.erl'], 'collectionURL': 'https://github.com', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'cow_spdy:parse/2'}, {'name': 'cow_spdy:inflate/2'}, {'name': 'cow_spdy:parse_headers/2'}, {'name': 'cow_spdy:parse_headers/4'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-43970', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-14T12:38:59.086048Z'} -
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
May. 13, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-409 Added Reference https://cna.erlef.org/cves/CVE-2026-43970.html Added Reference https://github.com/ninenines/cowlib/commit/16aad3fb9f81f5cda4d1706ff0c54237c619c282 Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-43970