ASN1SCC: Out-of-bounds read via unvalidated character index in ASN.1 string decoders
- Exploited
- No known exploitation
- Fix
- Fixed in 4.7.0.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 4.7.0.1.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 22/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
ASN1SCC, an open source ASN.1 compiler used in embedded systems, has an out-of-bounds read flaw in its string decoders for alphabets whose size is not a power of two. It can be reached remotely, without logging in, by a crafted message that causes the decoder to return a small amount of adjacent static program data as a valid decoded character. The full 128-character IA5String alphabet is not affected.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
ASN1SCC is an open source ASN.1 compiler for embedded systems. Prior to 4.7.0.1, the ACN runtime function Acn_Dec_String_CharIndex_private in asn1crt/asn1crt_encoding_acn.c and the generated uPER decoder InternalItem_string_with_alpha_decode in StgC/uper_c.stg do not validate a decoded character index before reading allowedCharSet. For string alphabets whose size is not a power of two, a crafted message can select an unused encoded index, read a small bounded window of adjacent static program constants, and return the byte as a successfully decoded character. The full 128-character IA5String alphabet is not affected. This issue is fixed in version 4.7.0.1.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity5.3/10CVSS 5.3
- No patch0/5No signal
What would change the score
- Would score about 67 if added to CISA KEV
- Would score about 62 if CISA's SSVC rates exploitation active
- Would score about 27 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 4.7.0.1.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- esa asn1scc
fixed in 4.7.0.1
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-75615
Is CVE-2026-75615 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-75615?
asn1scc: before 4.7.0.1.Source: cve.now feed data
How do I fix CVE-2026-75615?
Upgrade to a fixed version: 4.7.0.1.Source: cve.now feed data