Vulnerability in Erlang Erlang\/otp
CVE-2026-23943
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.006 (48.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Erlang Erlang\/otp
- Erlang Erlang\/ssh
- Erlang Otp — versions 3.0.1, 17.0, 07b8f441ca711f9812fad9e9115bab3c3aa92f79
Weakness classification (CWE)
References
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, vendor-advisory, Vendor Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Vendor Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Third Party Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Product, x_version-scheme)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)
Frequently asked questions
- What is CVE-2026-23943?
- CVE-2026-23943 is a medium-severity vulnerability in Erlang Erlang\/otp, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 5.3/10. Published 2026-03-13.
- How severe is CVE-2026-23943?
- Medium severity. CVSS v3 base score is 5.3 out of 10.