CVE-2026-46597Network attack vector

Unauthenticated server crash via padding-length underflow

Published May 22, 2026 · Updated May 22, 2026

Denial of service in golang.org/x/crypto/ssh before 0.52.0 allows remote attackers to crash SSH server processes via crafted AES-GCM packets. In gcmCipher.readCipherPacket, padding+1 is evaluated as byte arithmetic before conversion to int, so a padding value of 255 wraps to zero and bypasses the bounds check before unsigned slice-length subtraction underflows. The target must run an affected SSH server, negotiate AES-GCM, and process the malicious encrypted packet; confidentiality and integrity are unaffected.

CVSS severity7.5
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in golang.org/x/crypto/ssh before 0.52.0 allows remote attackers to crash SSH server processes via crafted AES-GCM packets. In gcmCipher.readCipherPacket, padding+1 is evaluated as byte arithmetic before conversion to int, so a padding value of 255 wraps to zero and bypasses the bounds check before unsigned slice-length subtraction underflows. The target must run an affected SSH server, negotiate AES-GCM, and process the malicious encrypted packet; confidentiality and integrity are unaffected.

The record

CVE
CVE-2026-46597
Published
May 22, 2026
Updated
May 22, 2026
Vendor
golang.org/x/crypto
Product
golang.org/x/crypto/ssh
Classifications
CWE-704, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 22, 2026CVE publishedPublication date reported by the CVE source.
  2. May 22, 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=0 <0.52.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

golang.org/x/crypto · golang.org/x/crypto/sshversion=0 <0.52.0

Published CVSS scores

7.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-704Incorrect Type Conversion or Cast
T1499Endpoint Denial of Service

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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