CVE-2026-33666 json
Zserio: Integer Overflow in BitStreamReader on 32-bit platforms
published 6mo ago modified 14d ago also EUVD-2026-25593
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 26%
- public exploits
- 0
- none known
Summary
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 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.
Patch / fix
- nds-association zserio 2.18.1
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Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 6mo ago
Exploit prediction
0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- github.com https://github.com/ndsev/zserio/security/advisories/GHSA-fjwv-6wcr-vqwj referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
- ndsev zserio
Classification
- Weakness
-
- CWE-190 Integer Overflow or Wraparound
References
-
github.com
/ndsev/zserio/security/advisories/GHSA-fjwv-6wcr-vqwj
exploit, mitigation, vendor-advisory
Sources
- CVE List CVE-2026-33666
- NVD CVE-2026-33666
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