CVE-2026-45257
Freebsd 14.3 … 15.1
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-45257 is a high-severity Write-what-where Condition (CWE-123) vulnerability in Freebsd Freebsd. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-16 (Memory Protection) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-39780
Vulnerability Data
The KTLS receive path decrypted each record in place, assuming that the mbufs holding received data were anonymous and safe to modify. This assumption does not hold for data placed on a socket by sendfile(2), which can reference file-backed memory…
more
directly through non-anonymous M_EXTPG pages or EXT_SFBUF mbufs. When the sender transmits such data over a loopback connection without enabling KTLS on the transmit side, the file-backed mbufs reach the receiver's decryption path unchanged. Decrypting a record in place then overwrites the backing file's page cache instead of a private copy of the data. An unprivileged local user who can read a file can overwrite its contents with data of their choosing by sending the file over a loopback connection on which they have enabled KTLS receive. The write modifies the page cache directly, so it bypasses file flags such as schg and is written back to disk. By overwriting a setuid binary or other trusted file, a local user can escalate privileges, potentially gaining full control of the affected system.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 4 hardening rules · 4 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Memory-protection mechanisms block unauthorized writes to arbitrary locations even if a write-what-where primitive exists.
Secure engineering principles require memory-safe coding and bounds checking that eliminate the root cause of write-what-where flaws.
Process isolation confines the blast radius of an arbitrary write so it cannot affect other domains.
Input validation directly stops malformed data from triggering buffer overflows that produce arbitrary write-what-where conditions.
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.
Secure SDLC practices directly prevent arbitrary write conditions via safe coding, bounds checking, and memory-safe constructs.
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.
Security testing in development and acceptance can detect write-what-where conditions before deployment.
Secure development lifecycle practices directly reduce the likelihood of write-what-where flaws such as buffer overflows.
Application security requirements can mandate input validation and bounds checking that mitigate arbitrary write conditions.
Secure architecture and engineering principles discourage unsafe memory handling that leads to write-what-where vulnerabilities.
Secure coding standards explicitly forbid unsafe buffer operations that enable arbitrary memory writes.
Change management processes help ensure security fixes for such weaknesses are properly deployed.
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-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-123
RHEL 8 (1 rule)
- V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-123
Windows 10 (1 rule)
- V-220727 Structured Exception Handling Overwrite Protection (SEHOP) must be enabled. prevents CWE-123
Windows 11 (1 rule)
- V-253284 Structured Exception Handling Overwrite Protection (SEHOP) must be enabled. prevents CWE-123