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Vulnerabilities

Vulnerability · GHSA-h2v8-394m-p7vv

Rustls: Brotli certificate decompression can allocate an attacker-controlled amount of memory up to 1 GiB before authentication.

Published Oct 27, 2026 · catalog updated Oct 27, 2026 · Rustls: Brotli certificate decompression

Last checked Oct 28, 2026, 11 days ago.

Open the advisory

Exploitation likelihood is not on this record for GHSA-h2v8-394m-p7vv. A missing EPSS score is not a low risk. Compare Rustls: Brotli certificate decompression with the linked advisory before you change production.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Rustls: Brotli certificate decompression).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
  • EPSS is missing. A missing score is not a low risk.
Severity
Low3.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
Awaiting synchronization with FIRST
Remediation
Version ranges on file
Affected products
crates.io rustls · rust rustls

### Summary The built-in (but disabled by default) Brotli certificate decoder bounds the output buffer but accepts an input-selected history window. A header of five bytes can specify a 1 GiB window allocation. A peer can abort a process whose allocator cannot satisfy that request. A client must enable Brotli and connect to the peer; a server must enable Brotli and request a client certificate. Neither direction requires a trusted attacker certificate. ### Details rustls calls which enables Brotli's large-window extension. rustls applies a limit to certificates, but this applies to the decompressed result, and not to any internal allocations the process requires. ### Impact Client applications that enable the feature will be vulnerable to malicious servers. Server applications that enable the feature and enable client authentication will be vulnerable to malicious clients. Potential for denial of service due to memory exhaustion from peers sending malicious Brotli-encoded certificates, for applications that enable Brotli decompression. ### Acknowledgement Thanks to OpenAI [OutboundDisclosures@openai.com](mailto:OutboundDisclosures@openai.com) for the disclosure.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • crates.io rustls0 → 0.23.46
  • crates.io rustls0.24.0-dev.1 → 0.24.0-dev.2
  • rust rustls< 0.23.46
  • rust rustls>= 0.24.0-dev.1, < 0.24.0-dev.2

How to fix GHSA-h2v8-394m-p7vv

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

Exploitation likelihood is not on this record for GHSA-h2v8-394m-p7vv. A missing EPSS score is not a low risk. Compare Rustls: Brotli certificate decompression with the linked advisory before you change production.

Which versions are affected?

Compare what you have installed with 0 → 0.23.46, 0.24.0-dev.1 → 0.24.0-dev.2, < 0.23.46, >= 0.24.0-dev.1, < 0.24.0-dev.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-770: Allocation of Resources Without Limits or Throttling. EPSS is not on this record yet. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 27, 2026 · GitHub Advisory Database

    Detected

    ### Summary The built-in (but disabled by default) Brotli certificate decoder bounds the output buffer but accepts an input-selected history window. A header of five bytes can specify a 1 GiB window allocation. A peer can abort a process whose allocator cannot satisfy that request. A client must enable Brotli and connect to the peer; a server must enable Brotli and request a client certificate. Ne

  2. Oct 27, 2026 · GitHub Advisory Database

    Fix available

    rustls fixed in 0.23.46; rustls fixed in 0.24.0-dev.2

  3. Oct 27, 2026 · GitHub Advisory Database

    Fix available

    rustls fixed in 0.23.46

  4. Oct 27, 2026 · GitHub Advisory Database

    Fix available

    rustls fixed in 0.24.0-dev.2

  5. Oct 27, 2026 · GitHub Advisory Database

    Updated

    ### Summary The built-in (but disabled by default) Brotli certificate decoder bounds the output buffer but accepts an input-selected history window. A header of five bytes can specify a 1 GiB window allocation. A peer can abort a process whose allocator cannot satisfy that request. A client must enable Brotli and connect to the peer; a server must enable Brotli and request a client certificate. Ne

Sources

References

Freshness

Last verified in this catalog Oct 27, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • GitHub Advisory DatabaseOct 28, 2026
  • OpenSSF OSV / OSV ScannerOct 28, 2026