Security Resilience

CVE-2023-25136

Memory Safety in Fedoraproject Fedora 37 … 38

Public PoCHigh EPSSMemory Safety
Published
03 February 2023
Modified
28 May 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
EPSS Score 0.90 99.8th percentile
Risk Priority 76 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-25136 is a medium-severity Double Free (CWE-415) vulnerability in Fedoraproject Fedora. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Steganography (T1001.002); ranked in the top 0.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

OpenSSH server (sshd) version 9.1 contains a double-free vulnerability (CWE-415) during handling of options.kex_algorithms. The flaw was introduced in that release and is fixed in OpenSSH 9.2, affecting the sshd daemon in its default configuration.

An unauthenticated remote attacker can trigger the double free over the network to jump to an arbitrary location in the sshd address space. Third-party analysis notes that remote code execution is theoretically possible, although the CVSS 6.5 rating reflects high attack complexity and limits impact primarily to integrity and availability.

The referenced oss-security mailing list threads discuss the issue and confirm availability of the 9.2 patch that eliminates the double-free condition.

The associated EPSS score reached a peak of 0.9097 with a current value of 0.8833.

EU & UK References

Vulnerability Data

OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd…

more

address space. One third-party report states "remote code execution is theoretically possible."

CWE(s)
CWE-415

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
attack.mitre.org →
T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
attack.mitre.org →
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-28464Same product class: NAS / storage appliance
CVE-2021-22600Same product class: NAS / storage appliance
CVE-2023-26545Same product class: NAS / storage appliance
CVE-2023-27537Same product class: NAS / storage appliance
CVE-2024-27127Same product class: NAS / storage appliance
CVE-2024-53698Same product class: NAS / storage appliance
CVE-2020-8625Same product: Fedoraproject Fedora
CVE-2021-43267Same product: Fedoraproject Fedora
CVE-2024-1086Same product: Fedoraproject Fedora
CVE-2024-41965Same product class: NAS / storage appliance

Affected Assets

openbsd
openssh
9.1
fedoraproject
fedora
37, 38
netapp
ontap select deploy administration utility
all versions
netapp
a250 firmware
all versions
netapp
500f firmware
all versions
netapp
c250 firmware
all versions

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 1 hardening rule · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match
blocks

Secure SDLC practices directly prevent double-free errors via static analysis, safe memory APIs, and testing.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.5.32 Intellectual property rights partial match
removes

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248590 OL 8 must clear the page allocator to prevent use-after-free attacks. blocks CWE-415

References