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TI-2026-38709 Aliases CVE-2026-53670

PREVAIL: Non-singleton typeset in add() skips offset update, allowing OOB access to pass eBPF verification

Priority HIGH 81CWE-682Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

PREVAIL is a Polynomial-Runtime EBPF Verifier using an Abstract Interpretation Layer. Prior to version 0.2.4, in the Prevail eBPF verifier, EbpfTransformer::add() silently skips offset-variable updates when the destination register carries a non-singleton typeset (two or more simultaneously possible pointer types). Subsequent bounds checks use the stale offset and accept out-of-bounds memory accesses, so a crafted BPF program passes verification even though it would corrupt memory at runtime. This issue has been patched in version 0.2.4.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00507 43rd percentileScored 2026-11-07
Fix Fixed prevail (vbpf): 0.2.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
vbpfprevailbefore 0.2.40.2.4Patch availableCNA
  • prevail Vendorvbpf Affected before 0.2.4 Fixed in 0.2.4 Patch available CNA

Remediation

  • Fix · CNA prevail (vbpf) Fixed in 0.2.4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-53670

References

Other 3

  • TI-2026-38710 PREVAIL: Context-write no-op in do_mem_store allows unsafe eBPF programs to pass verification CVSS 4.0CRITICAL 9.3
  • TI-2026-38729 PREVAIL: ALU32 pointer arithmetic accepted without is64 gate — verifier emits false PASS for pointer-corrupting programs CVSS 4.0HIGH 8.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences