CVE-2025-55398: n/a
Source CVE Database V5
Not known to be exploited · CVSS 9.8 Critical.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
AI-suggested
To mitigate CVE-2025-55398 effectively, European organizations should: 1) Conduct an immediate inventory to identify all systems and applications using mouse07410 asn1c or its forks, especially those handling UPER-encoded ASN.1 data. 2) Engage with vendors and open-source communities to obtain or develop patches or updated versions that enforce proper INTEGER constraints for values exceeding 32 bits. 3) Implement strict input validation and filtering at network boundaries to detect and block malformed ASN.1 UPER data packets, potentially using deep packet inspection tools tailored for ASN.1 protocols. 4) Employ network segmentation to isolate vulnerable systems, limiting exposure to external networks. 5) Monitor network traffic and system logs for anomalous ASN.1 decoding errors or unusual activity indicative of exploitation attempts. 6) Consider deploying runtime application self-protection (RASP) or memory protection mechanisms (e.g., ASLR, DEP) to reduce exploitation success. 7) Prepare incident response plans specific to ASN.1-related attacks, including rapid patch deployment and system recovery procedures. 8) Stay informed about updates from the mouse07410 asn1c project and security advisories to apply fixes promptly once available.
Description
An issue was discovered in mouse07410 asn1c thru 0.9.29 (2025-03-20) - a fork of vlm asn1c. In UPER (Unaligned Packed Encoding Rules), asn1c-generated decoders fail to enforce INTEGER constraints when the bound is positive and exceeds 32 bits in length, potentially allowing incorrect or malicious input to be processed.