Cyber 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

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 Exploitation for Client Execution (T1203); 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

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
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-2023-27043Same product: Fedoraproject Fedora

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 full match
prevents

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.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect double-free conditions before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle includes memory-safety practices that can prevent double-free bugs.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate memory-safety rules that reduce double-free risk.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles can prescribe safe memory-management patterns.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly address proper use of free() and similar functions.

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` (authoritative 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. prevents CWE-415

References