Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-93599— rustls-webpki before 0.103.13 Panic via empty BIT STRING

Quick assessment

Affected
rustls webpki
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

rustls 和 webpki 库（版本 up to 0.103.12，以及 0.104.0-alpha.7 之前的 0.104.0-alpha 系列版本）在 中的 函数中存在一个可触发的 panic（程序崩溃）漏洞。 具体来说，输入校验未能拒绝一个命名位（named-bit）BIT STRING，其内容恰好为 （即零个填充位且没有数据字节）。这导致 在空切片上发生下溢：在 debug 模式下表现为减法溢出（subtract-with-overflow），在 release 模式下表现为数组索引越界（index-o

CVSS 7.5 · High

Affected Version Matrix 2

VendorProduct Version RangeStatus
rustls webpki < 0.103.13 affected
0.104.0-alpha.1< 0.104.0-alpha.7 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-93599

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
rustls-webpki before 0.103.13 Panic via empty BIT STRING
Source: CVE Program / CVE List V5
Vulnerability Description
rustls-webpki through 0.103.12 (and 0.104.0-alpha releases before 0.104.0-alpha.7) contains a reachable panic in bit_string_flags() in src/der.rs. The input guard fails to reject a named-bit BIT STRING whose content is exactly [0x00] (zero padding bits and no data bytes), so raw_bits.len() - 1 underflows on the empty slice and the subsequent index operation panics (subtract-with-overflow in debug, index-out-of-bounds in release). The condition is reachable through the public API BorrowedCertRevocationList::from_der() when a CRL contains an issuingDistributionPoint extension with such an onlySomeReasons value. Exploitation requires an application that explicitly opts in to CRL revocation checking by passing RevocationOptions to verify_for_usage() and that parses CRL bytes obtained from a source the attacker can influence; the default rustls configuration, which does not use RevocationOptions, is unaffected. A crafted CRL causes a denial of service via the panic. Fixed in 0.103.13 and 0.104.0-alpha.7.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
整数下溢(超界折返)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
rustls webpki 0 ~ 0.103.13 -

II. Public POCs for CVE-2026-93599

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-93599

请登录查看更多情报信息。

Other References for CVE-2026-93599 (2)

Same Patch Batch · rustls · 2026-09-18 · 4 CVEs total

CVE-2026-93602 4.4 MEDIUM rustls-webpki before 0.103.10 CRL Revocation Check Bypass
CVE-2026-93601 2.2 LOW rustls webpki 0.101.0 before 0.103.12 Name Constraint Bypass
CVE-2026-93600 2.2 LOW rustls webpki Name Constraints URI Validation Bypass

IV. Related Vulnerabilities

Same product: webpki
Same vendor: rustls
Same weakness: CWE-191

V. Comments for CVE-2026-93599

No comments yet

Leave a comment