GHSA-gg47-62fq-vrhpPublished

rustls before 0.23.46 Denial of Service via Brotli Certificate Decompression

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cve-program · CVE-2026-123610

Published

rustls before 0.23.46 contains an uncontrolled memory allocation flaw in its optional Brotli certificate decompression, which limits decompressed output size but accepts an input-selected large history window. Malicious peers can send a certificate with a five-byte Brotli header requesting up to 1 GiB before authentication, aborting Brotli-enabled clients or client-authenticating servers whose allocator cannot satisfy the request.

Source published: 8 Nov 2026 01:38:35 UTC
Source modified: 9 Nov 2026 13:52:03 UTC
Saved here: 9 Nov 2026 15:02:10 UTC
Source terms: CVE Program Terms of Use

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CVSS 4.0 · 6.3 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS 3.1 · 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

euvd · EUVD-2026-119369

Published

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EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

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datePublished: Nov 8, 2026, 1:38:35 AM

dateUpdated: Nov 9, 2026, 1:52:03 PM

1 related source bulletins · separate from aliases

msrc_CVE-2026-123610: rustls before 0.23.46 Denial of Service via Brotli Certificate Decompression

CVE-2026-123610

Source published: Nov 8, 2026, 1:38:35 AM (timezone not stated)
Source modified: Nov 9, 2026, 1:52:03 PM (timezone not stated)
Saved here: 14 Nov 2026 11:58:43 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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EUVD CVSS 4.0 · 6.3 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

nvd · CVE-2026-123610

Published

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NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Awaiting Analysis

Weakness classifications: CWE-770

Original publisher date fields

published: 2026-11-08T02:16:56.267

lastModified: 2026-11-12T21:30:23.870

Source published: 8 Nov 2026 02:16:56 UTC
Source modified: 12 Nov 2026 21:30:23 UTC
Saved here: 14 Nov 2026 12:57:57 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

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CVSS 4.0 · [email protected] · Secondary · 6.3 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Secondary · 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

osv · GHSA-h2v8-394m-p7vv

Published

### 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 `BrotliDecompress` 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 `brotli` feature will be vulnerable to malicious servers. Server applications that enable the `brotli` 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 [[email protected]](mailto:[email protected]) for the disclosure.

Source published: 27 Oct 2026 16:08:36 UTC
Source modified: 8 Nov 2026 10:55:59 UTC
Saved here: 8 Nov 2026 11:07:08 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Publisher rating · LOW

osv · RUSTSEC-2026-0348

Published

The built-in Brotli certificate decompressor (enabled by the non-default `brotli` crate feature) bounded the size of the decompressed output, but accepted a peer-selected history window. Brotli's large-window extension was enabled, so a five-byte header could cause an allocation of 1 GiB. A peer can abort a process whose allocator cannot satisfy that request. No trusted certificate is required by the attacker. Affected configurations are: - clients that enable the `brotli` feature and connect to a malicious server, and - servers that enable the `brotli` feature and request client certificates. Applications that do not enable the `brotli` feature are not affected.

Source published: 14 Oct 2026 12:00:00 UTC
Source modified: 9 Nov 2026 09:21:20 UTC
Saved here: 9 Nov 2026 10:04:30 UTC
Source terms: OSV · upstream source license applies

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CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L