CVE-2026-23943
published 2026-03-13CVE-2026-23943: Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in Erlang OTP ssh (ssh_transport modules) allows Denial of Service via Resource…
PriorityP432medium5.3CVSS 3.1
AVNACLPRNUINSUCNINAL
EPSS
0.64%
48.5th percentile
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
* [email protected]: 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.
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | erlang | < erlang 1:27.3.4.9+dfsg-1 (forky) | erlang 1:27.3.4.9+dfsg-1 (forky) |
| erlang | erlang_otp | >= 17.0 < 26.2.5.18 | 26.2.5.18 |
| erlang | erlang_otp | >= 27.0 < 27.3.4.9 | 27.3.4.9 |
| erlang | erlang_otp | >= 28.0 < 28.4.1 | 28.4.1 |
| erlang | erlang_ssh | >= 3.0.1 < 5.1.4.14 | 5.1.4.14 |
| erlang | erlang_ssh | >= 5.2 < 5.2.11.6 | 5.2.11.6 |
| erlang | erlang_ssh | 5.5 – 5.5.1 | — |
| erlang | otp | >= 07b8f441ca711f9812fad9e9115bab3c3aa92f79 < * | * |
| erlang | otp | >= 17.0 < * | * |
| erlang | otp | >= 3.0.1 < * | * |
| msrc | azl3_erlang_26.2.5.17-1_on_azure_linux_3.0 | — | — |
| msrc | cbl2_erlang_25.3.2.21-4_on_cbl_mariner_2.0 | — | — |
CVSS provenance
nvdv3.15.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
nvdv4.06.9MEDIUMCVSS: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
osv6.9MEDIUM
vendor_debian6.9MEDIUM
vendor_msrc6.9MEDIUM
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Microsoft
Pre-auth SSH DoS via unbounded zlib inflate
vendor_msrc·2026-03-10·CVSS 6.9
CVE-2026-23943 [MEDIUM] CWE-409 Pre-auth SSH DoS via unbounded zlib inflate
Pre-auth SSH DoS via unbounded zlib inflate
Mariner: Mariner
EEF: EEF
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Reference: https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade
Debian
CVE-2026-23943: erlang - Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in ...
vendor_debian·2026·CVSS 6.9
CVE-2026-23943 [MEDIUM] CVE-2026-23943: erlang - Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in ...
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 * [email protected]: 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 assoc
OSV
CVE-2026-23943: Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in Erlang OTP ssh (ssh_transport modules) allows Denial of Service via Re
osv·2026-03-13·CVSS 6.9
CVE-2026-23943 [MEDIUM] CVE-2026-23943: Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in Erlang OTP ssh (ssh_transport modules) allows Denial of Service via Re
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 * [email protected]: 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 assoc
No detection rules found.
No public exploits indexed.
https://cna.erlef.org/cves/CVE-2026-23943.htmlhttps://github.com/erlang/otp/commit/0c1c04b191f6ab940e8fcfabce39eb5a8a6440a4https://github.com/erlang/otp/commit/43a87b949bdff12d629a8c34146711d9da93b1b1https://github.com/erlang/otp/commit/93073c3bd338c60cd2bae715ce6a1d4ffc1a8fd3https://github.com/erlang/otp/security/advisories/GHSA-c836-qprm-jw9rhttps://osv.dev/vulnerability/EEF-CVE-2026-23943https://www.erlang.org/doc/system/versions.html#order-of-versions
2026-03-13
Published