CVE-2026-81879 radareorg CVE debrief

Who should care

Defenders responsible for radare2 installations, particularly those using versions prior to 6.2.0, should assess exposure and prioritize updates to prevent potential exploitation. This includes reviewing and updating affected systems and tools, monitoring for potential exploitation attempts, and ensuring that security teams are aware of the vulnerability and its potential impact. Additionally, defenders should review the supplied official advisory or CVE 6

Why it matters

CVE-2026-81879 is a medium-severity vulnerability in radare2's ELF PN_XNUM handling. Defenders should prioritize updating to version 6.2.0 or later to prevent potential exploitation and denial of service.

• Denial of service due to process termination
• Potential for memory disclosure, although not demonstrated
• Need for version verification and updates
• Importance of monitoring for exploitation attempts

Technical summary

The radare2 ELF PN_XNUM handling vulnerability occurs when processing a crafted ELF file with e_phnum = 0xffff and a much smaller resolved count in shdr[0].sh_info. This causes consumers to iterate beyond the allocated program-header array, resulting in a heap out-of-bounds read and process termination. The vulnerability is triggered by a specific ELF file structure, and defenders should prioritize updating to version 6.2.0 or later to prevent exploitation of this vulnerability. The issue is fixed in version 6.2.0, which addresses the vulnerability by properly handling the ELF PN_XNUM.

Defensive priority

Defenders should prioritize updating radare2 to version 6.2.0 or later to prevent exploitation of this vulnerability.

Recommended defensive actions

• Update radare2 to version 6.2.0 or later
• Review and update affected systems and tools
• Monitor for and respond to potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The vulnerability is triggered by processing a crafted ELF file with e_phnum = 0xffff and a much smaller resolved count in shdr[0].sh_info. Consumers iterated beyond the allocated program-header array, causing a heap out-of-bounds read and process termination.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.