CVE-2026-115906 zip-rs CVE debrief

Who should care

Defenders responsible for systems that process zip archives with AES-encrypted entries should assess exposure and prioritize patching for vulnerable zip crate versions. This includes verifying inventory of systems, assessing exposure, and implementing compensating controls to detect and prevent malicious archive processing.

Why it matters

The zip crate vulnerability allows an attacker to bypass HMAC authentication for AES-encrypted entries, potentially leading to unauthenticated plaintext being returned. Defenders should prioritize verifying inventory and assessing exposure for systems that process zip archives with AES-encrypted entries.

• An attacker can bypass HMAC authentication for AES-encrypted zip entries, allowing unauthenticated plaintext to be returned.
• Defenders must verify inventory and assess exposure for systems that process zip archives with AES-encrypted entries.
• Successful exploitation requires the attacker to modify the archive and the victim to process it.

Technical summary

The zip crate does not properly verify the authentication code for AES-encrypted entries when the reader's byte counter lands exactly on zero or when the bounded entry reader reaches the archive's actual EOF before the attacker-controlled, header-declared `compressed_size`. This allows an attacker to bypass HMAC authentication, potentially leading to unauthenticated plaintext being returned. The vulnerability affects systems that process zip archives with AES-encrypted entries. Defenders should prioritize verifying inventory and assessing exposure for systems that process zip archives with AES-encrypted entries.

Defensive priority

Defenders should prioritize verifying inventory and assessing exposure for systems that process zip archives with AES-encrypted entries.

Recommended defensive actions

• Verify inventory of systems that process zip archives with AES-encrypted entries
• Assess exposure and prioritize patching for vulnerable zip crate versions
• Implement compensating controls to detect and prevent malicious archive processing
• Review relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Evidence notes

The source corpus provides details on the vulnerability in the zip crate, specifically in the AES-encrypted entry handling. The CVE record was published on 2026-10-29T16:40:07.000Z and has not been modified since then. The vulnerability allows an attacker to bypass HMAC authentication for AES-encrypted entries, potentially leading to unauthenticated plaintext being returned. The zip crate does not properly verify the authentication code for AES-encrypted entries when the reader's byte counter lands exactly on zero or when the bounded

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.