CVE-2026-23943Network attack vector

Pre-auth memory exhaustion via unbounded zlib inflate

Published Mar 13, 2026 · Updated Mar 13, 2026

Compression-bomb handling in Erlang/OTP ssh allows remote attackers to exhaust memory and crash SSH clients or servers. ssh_transport:decompress/2 passes attacker-controlled compressed packet bodies to zlib:inflate without bounding the decompressed output. Default zlib negotiation activates after key exchange without authentication; [email protected] requires authentication, and repeated packets can trigger OOM termination on memory-constrained hosts.

CVSS severity6.9
Medium
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Compression-bomb handling in Erlang/OTP ssh allows remote attackers to exhaust memory and crash SSH clients or servers. ssh_transport:decompress/2 passes attacker-controlled compressed packet bodies to zlib:inflate without bounding the decompressed output. Default zlib negotiation activates after key exchange without authentication; [email protected] requires authentication, and repeated packets can trigger OOM termination on memory-constrained hosts.

The record

CVE
CVE-2026-23943
Published
Mar 13, 2026
Updated
Mar 13, 2026
Vendor
Erlang
Product
Erlang/OTP
Classifications
CWE-409, CAPEC-490, CAPEC-130, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=07b8f441ca711f9812fad9e9115bab3c3aa92f79 <* changes=[{"at":"43a87b949bdff12d629a8c34146711d9da93b1b1","status":"unaffected"},{"at":"93073c3bd338c60cd2bae715ce6a1d4ffc1a8fd3","status":"unaffected"},{"at":"0c1c04b191f6ab940e8fcfabce39eb5a8a6440a4","status":"unaffected"}]
  2. Affected versionversion=17.0 <* changes=[{"at":"28.4.1","status":"unaffected"},{"at":"27.3.4.9","status":"unaffected"},{"at":"26.2.5.18","status":"unaffected"}]
  3. Affected versionversion=3.0.1 <* changes=[{"at":"5.5.1","status":"unaffected"},{"at":"5.2.11.6","status":"unaffected"},{"at":"5.1.4.14","status":"unaffected"}]
  4. Affected versionversion=pkg:otp/[email protected] <pkg:otp/ssh@* changes=[{"at":"pkg:otp/[email protected]","status":"unaffected"},{"at":"pkg:otp/[email protected]","status":"unaffected"},{"at":"pkg:otp/[email protected]","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Erlang · Erlang/OTPversion=07b8f441ca711f9812fad9e9115bab3c3aa92f79 <* changes=[{"at":"43a87b949bdff12d629a8c34146711d9da93b1b1","status":"unaffected"},{"at":"93073c3bd338c60cd2bae715ce6a1d4ffc1a8fd3","status":"unaffected"},{"at":"0c1c04b191f6ab940e8fcfabce39eb5a8a6440a4","status":"unaffected"}]; version=17.0 <* changes=[{"at":"28.4.1","status":"unaffected"},{"at":"27.3.4.9","status":"unaffected"},{"at":"26.2.5.18","status":"unaffected"}]; version=3.0.1 <* changes=[{"at":"5.5.1","status":"unaffected"},{"at":"5.2.11.6","status":"unaffected"},{"at":"5.1.4.14","status":"unaffected"}]; version=pkg:otp/[email protected] <pkg:otp/ssh@* changes=[{"at":"pkg:otp/[email protected]","status":"unaffected"},{"at":"pkg:otp/[email protected]","status":"unaffected"},{"at":"pkg:otp/[email protected]","status":"unaffected"}]

Published CVSS scores

6.9Erlang/OTP GitHub Security AdvisoryCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-409Improper Handling of Highly Compressed Data (Data Amplification)
CAPEC-490Amplification
CAPEC-130Excessive Allocation
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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