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Use After Free

CVE-2026-45185

High
9.8/10

Summary

Exim 4.97.x prior to 4.99.3, in certain GnuTLS configurations, has a remotely reachable use-after-free in the BDAT body parsing path. It is triggered when a client sends a TLS "close_notify" mid-body during a CHUNKING transfer, followed by a final cleartext byte on the same TCP connection. This can lead to heap corruption. An unauthenticated network attacker exploiting this vulnerability could execute arbitrary code.

  • LOW
  • NETWORK
  • HIGH
  • UNCHANGED
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-416 - Use After Free

Use-after-free (UaF) vulnerability occurs when the application is using a pointer to memory that has been freed. Any attempt to read/write to a buffer after it is de-allocated allows memory corruption, sensitive information exposure, and can potentially lead to arbitrary code execution.

References

Advisory Timeline

  • Published