CVE-2026-81881 — radare2: Heap out-of-bounds read in radare2 Mach-O Swift metadata parser
radare2 is a UNIX-like reverse engineering framework and command-line toolset. Prior to 6.2.0, radare2's Mach-O Swift field-metadata parser was vulnerable because a relative Swift field pointer could be lower than the field-metadata section base, making subtraction produce a negative logical index. The vulnerability is triggered by parsing Swift type and class metadata from a crafted Mach-O file. The derived index was used to read four bytes immediately before the allocated field-metadata buffer. This can cause incorrect metadata processing or process termination; no attacker-observable memory disclosure has been demonstrated. This issue is fixed in version 6.2.0.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented mitigation — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Radare Radare2, Radareorg Radare2).
- Apply the fixed version or the patch documented under Remediation.
- Exploitation requires user interaction: tighten email/web filtering and warn affected users.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 4.4 | CVSS 3.1 | Medium | 1.8 | 2.5 | nvd@nist.gov via NIST National Vulnerability Database |
| 3.3 | CVSS 3.1 | Low | 1.8 | 1.4 | security-advisories@github.com via NIST National Vulnerability Database |
| 3.3 | CVSS 3.1 | Low | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · radareorg/radare2
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 4.4
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
4 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-81886 radare2: Uncontrolled memory allocation in radare2 dmp64 parser 23d
- Medium CVE-2026-81882 radare2: Missing string termination causes heap out-of-bounds read in radare2 bplist parser 23d
- Low CVE-2026-81883 radare2: Out-of-bounds Read at the end of string in the LUA 5.3 bytecode 23d
- Medium CVE-2026-81885 radare2: Infinite relocation-chain loop causes denial of service in radare2 NE parser 23d
- Low CVE-2026-81884 radare2: Heap out-of-bounds read in radare2 Mach-O LC_DATA_IN_CODE parser 23d
- Medium CVE-2026-81879 radare2: Heap out-of-bounds read in radare2 ELF PN_XNUM handling 23d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-81881 is "radare2: Heap out-of-bounds read in radare2 Mach-O Swift metadata parser", rated Medium. It affects Radare2 (Radare); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.4 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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