CVE-2022-4639Network attack vector

Memory disclosure via packet-dump format string

Published Dec 21, 2022 · Updated Apr 14, 2025

Format-string injection in sslh 2.0-rc1 allows remote attackers to disclose process memory via crafted traffic when packet dumping is enabled. The probe.c hexdump function passes packet-derived printable bytes directly to print_message as its format string instead of using a fixed %s format. The nondefault verbose-packets setting is required, and no stable release contained the affected code.

CVSS severity9.8
Critical
EPSS probability0.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Format-string injection in sslh 2.0-rc1 allows remote attackers to disclose process memory via crafted traffic when packet dumping is enabled. The probe.c hexdump function passes packet-derived printable bytes directly to print_message as its format string instead of using a fixed %s format. The nondefault verbose-packets setting is required, and no stable release contained the affected code.

The record

CVE
CVE-2022-4639
Published
Dec 21, 2022
Updated
Apr 14, 2025
Vendor
Yves Rutschle
Product
sslh
Classifications
CWE-119, CWE-134, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 21, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 2025Record 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=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Yves Rutschle · sslhversion=n/a

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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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-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-134Use of Externally-Controlled Format String
T1190Exploit Public-Facing Application

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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