Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-2026-33666 is a high-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Nds-Association Zserio. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 41th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — 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-2026-33666 is an integer overflow vulnerability (CWE-190) in the Zserio framework, which provides compact and efficient serialization of structured data with low overhead. Versions prior to 2.18.1 are affected, specifically in the BitStreamReader.h file within the readBytes() and readString() functions. There, the setBitPosition() bounds check receives an overflowed value, allowing it to be completely bypassed. This leads the code to attempt reading 512 MB (len bytes) from a buffer that is only a few bytes long, resulting in a segmentation fault. The issue carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and was published on 2026-04-24.
The vulnerability can be exploited remotely by unauthenticated attackers with low complexity and no user interaction required. An attacker simply needs to supply crafted input to a Zserio deserializer invoking readBytes() or readString(), triggering the overflowed bounds check bypass and subsequent buffer overread. Successful exploitation causes a segmentation fault, resulting in denial of service via application crash and high impact to availability, though confidentiality and integrity remain unaffected.
According to the GitHub security advisory (GHSA-fjwv-6wcr-vqwj), the vulnerability is fixed in Zserio version 2.18.1. Mitigation involves upgrading to 2.18.1 or later. Additional details are available at https://github.com/ndsev/zserio/security/advisories/GHSA-fjwv-6wcr-vqwj.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25593
Vulnerability Data
Zserio is a framework for serializing structured data with a compact and efficient way with low overhead. Prior to 2.18.1, in BitStreamReader.h readBytes() / readString(), the setBitPosition() bounds check receives the overflowed value and is completely bypassed. The code then…
more
reads len bytes (512 MB) from a buffer that is only a few bytes long, causing a segmentation fault. This vulnerability is fixed in 2.18.1.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.2.6
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (static analysis, fuzzing, unit tests) directly finds integer overflow defects before deployment.
Secure engineering principles require use of safe arithmetic constructs or language features that structurally eliminate integer overflow during calculation.
Input validation enforces bounds on values before arithmetic, stopping the conditions that trigger overflow or wraparound.
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 require use of safe arithmetic, bounds checks, and testing that prevent integer 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.
Security testing in development can detect integer overflows before release.
Secure coding standards explicitly forbid unsafe integer operations and mandate overflow-safe constructs.