CVE-2026-23943

MEDIUM EPSS 46.3%
Published Mar 13, 20263mo ago · Modified May 21, 20261mo ago
6.9 CVSS 4.0
Medium
Find Similar
Published Mar 13, 2026 3mo ago
Last Modified May 21, 2026 1mo ago

Description

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 until OTP 28.4.1, 27.3.4.9 and 26.2.5.18 corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.

CVSS Details

Base Score
6.9
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
46.3% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-409

Affected Products 6

VendorProductVersionRange
erlangerlang\/otp*≥17.0  –  <26.2.5.18
erlangerlang\/otp*≥27.0  –  <27.3.4.9
erlangerlang\/otp*≥28.0  –  <28.4.1
erlangerlang\/ssh*≥3.0.1  –  <5.1.4.14
erlangerlang\/ssh*≥5.2  –  <5.2.11.6
erlangerlang\/ssh*≥5.5  –  ≤5.5.1

References 7

  • cna.erlef.org https://cna.erlef.org/cves/CVE-2026-23943.html
    Vendor Advisory
  • github.com https://github.com/erlang/otp/commit/0c1c04b191f6ab940e8fcfabce39eb5a8a6440a4
    Patch
  • github.com https://github.com/erlang/otp/commit/43a87b949bdff12d629a8c34146711d9da93b1b1
    Patch
  • github.com https://github.com/erlang/otp/commit/93073c3bd338c60cd2bae715ce6a1d4ffc1a8fd3
    Patch
  • github.com https://github.com/erlang/otp/security/advisories/GHSA-c836-qprm-jw9r
    Vendor Advisory
  • osv.dev https://osv.dev/vulnerability/EEF-CVE-2026-23943
    Third Party Advisory
  • erlang.org https://www.erlang.org/doc/system/versions.html#order-of-versions
    Product

Remediation

  • github.com https://github.com/erlang/otp/commit/0c1c04b191f6ab940e8fcfabce39eb5a8a6440a4
    Patch
  • github.com https://github.com/erlang/otp/commit/43a87b949bdff12d629a8c34146711d9da93b1b1
    Patch
  • github.com https://github.com/erlang/otp/commit/93073c3bd338c60cd2bae715ce6a1d4ffc1a8fd3
    Patch