CVE-2026-23943 Affecting erlang package, versions <1:25.2.3+dfsg-1+deb12u4


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.64% (46th percentile)

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  • Snyk IDSNYK-ECHOLATEST-ERLANG-18353407
  • published28 Jul 2026
  • disclosed13 Mar 2026

Introduced: 13 Mar 2026

CVE-2026-23943  (opens in a new tab)

How to fix?

Upgrade Echo:latest erlang to version 1:25.2.3+dfsg-1+deb12u4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream erlang package and not the erlang package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in Erlang OTP ssh (ssh_transport modules) allows Denial of Service via Resource Depletion.

The SSH transport layer advertises legacy zlib compression by default and inflates attacker-controlled payloads pre-authentication without any size limit, enabling reliable memory exhaustion DoS.

Two compression algorithms are affected:

  • zlib: Activates immediately after key exchange, enabling unauthenticated attacks
  • zlib@openssh.com: Activates post-authentication, enabling authenticated attacks

Each SSH packet can decompress ~255 MB from 256 KB of wire data (1029:1 amplification ratio). Multiple packets can rapidly exhaust available memory, causing OOM kills in memory-constrained environments.

This vulnerability is associated with program files lib/ssh/src/ssh_transport.erl and program routines ssh_transport:decompress/2, ssh_transport:handle_packet_part/4.

This issue affects OTP from OTP 17.0 before OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to ssh from 3.0.1 before 5.5.1, 5.2.11.6 and 5.1.4.14.

CVSS Base Scores

version 3.1