Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-35547 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Freebsd Freebsd. Its CVSS base score is 8.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 25th 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 SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-35547 is a heap-based buffer overflow vulnerability in the libnv library, stemming from a failure to properly validate the size of incoming message headers during processing. This flaw, associated with CWE-122 and CWE-130, allows out-of-bounds writes beyond heap allocations in affected FreeBSD systems utilizing libnv.
The vulnerability can be exploited remotely over the network (AV:N) by attackers requiring no privileges (PR:N) and no user interaction (UI:N), though it demands high attack complexity (AC:H) with an unchanged impact scope (S:U). Successful exploitation may trigger system crashes or panics, and it could enable unprivileged users to achieve privilege escalation, with a CVSS v3.1 base score of 8.1 indicating high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H).
The FreeBSD Security Advisory SA-26:17 addresses this issue in libnv, with full details available at https://security.freebsd.org/advisories/FreeBSD-SA-26:17.libnv.asc.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-26355
Vulnerability Data
When processing the header of an incoming message, libnv failed to properly validate the message size. The lack of validation allows a malicious program to write outside the bounds of a heap allocation. This can trigger a crash or system…
more
panic, and it may be possible for an unprivileged user to exploit the bug to elevate their privileges.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (including fuzzing and memory-error detectors) can discover heap overflows after they have been coded.
Input validation enforces bounds checking on data written to heap buffers, directly stopping the overflow condition from being introduced.
Security engineering principles require use of memory-safe constructs and bounds-checked allocation routines that avoid introducing heap overflows.
Memory-protection mechanisms limit the ability of a heap overflow to execute attacker-controlled code or corrupt adjacent structures.
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.
Vulnerability scanning and recording can discover heap-overflow flaws but does not prevent their introduction in code.
Timely patching removes known heap-overflow instances after they exist.
Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.
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.
Secure development lifecycle mandates practices that reduce the likelihood of introducing heap overflows.
Application security requirements can specify bounds-checking and safe memory APIs that mitigate heap overflows.
Secure architecture and engineering principles include memory-safety and input-validation controls that address heap overflows.
Secure coding standards directly prescribe techniques (safe functions, bounds checks) that prevent heap-based buffer overflows.
Security testing in development and acceptance can detect heap overflows before release.