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No exploitation reported

CVE-2026-61916

Apache bRPC: Out-of-bounds Read in URL and Header Lookup Tables on Unsigned-char Platforms

No exploitation reported by the sources we read.

  • Published2026-10-21
  • WeaknessCWE-125

Am I affected?

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Description

Out-of-bounds reads in URL parsing and case-insensitive header lookup in Apache bRPC before version 1.18.0 on platforms where plain char is unsigned, such as ARM64, allow remote attackers to cause a process crash and denial of service by sending crafted input containing bytes with the high bit set. Root Cause: Two 256-entry lookup tables are accessed through pointers biased by 128 so that valid indices are in the range -128 to 127. Input bytes are promoted from plain char to int without first normalizing them to the signed-char range. On affected platforms, bytes in the range 0x80 to 0xFF therefore become indices 128 to 255 and read up to 127 bytes beyond the end of the underlying tables. Affected Scenarios: A remotely accessible bRPC HTTP server on an affected platform can reach the vulnerable URL lookup through an unauthenticated request URI containing a high-bit byte. The case-insensitive lookup is also reachable when untrusted header names are processed through APIs such as the HTTP/2 HPACK path. HTTP/1 header names containing high-bit bytes are rejected by the HTTP/1 parser before reaching the vulnerable lookup. Builds where plain char is signed, which commonly include x86_64 builds, are not affected by this issue. How to Fix: Choose one of the following options: 1. Upgrade Apache bRPC to version 1.18.0 or later. 2. Apply the patch from https://github.com/apache/brpc/pull/3376 . The fix normalizes lookup-table indices to the signed-char range before accessing the biased tables.

Timeline

dates in UTC
  1. 2026-10-2112:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-31 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-61916?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-61916?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-61916 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2026-10-30
  • OpenCVESSVC decisionnone—
  • CISA-ADPCVSS 3.17.52026-10-30
  • CNAweakness (CWE)CWE-125read 2026-10-31
  • NVDweakness (CWE)CWE-125read 2026-10-27
  • FIRST EPSSEPSS score0.2 %2026-10-30

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-10-21
Last Modified
2026-10-30
NVD status
Deferred

Frequently asked questions

What is CVE-2026-61916?

Out-of-bounds reads in URL parsing and case-insensitive header lookup in Apache bRPC before version 1.18.0 on platforms where plain char is unsigned, such as ARM64, allow remote attackers to cause a process crash and denial of service by sending crafted input containing bytes with the high bit set. Root Cause: Two 256-entry lookup tables are accessed through pointers biased by 128 so that valid indices are in the range -128 to 127. Input bytes are promoted from plain char to int without first normalizing them to the signed-char range. On affected platforms, bytes in the range 0x80 to 0xFF therefore become indices 128 to 255 and read up to 127 bytes beyond the end of the underlying tables. Affected Scenarios: A remotely accessible bRPC HTTP server on an affected platform can reach the vulnerable URL lookup through an unauthenticated request URI containing a high-bit byte. The case-insensitive lookup is also reachable when untrusted header names are processed through APIs such as the HTTP/2 HPACK path. HTTP/1 header names containing high-bit bytes are rejected by the HTTP/1 parser before reaching the vulnerable lookup. Builds where plain char is signed, which commonly include x86_64 builds, are not affected by this issue. How to Fix: Choose one of the following options: 1. Upgrade Apache bRPC to version 1.18.0 or later. 2. Apply the patch from https://github.com/apache/brpc/pull/3376 . The fix normalizes lookup-table indices to the signed-char range before accessing the biased tables.

Is CVE-2026-61916 actively exploited?

Active exploitation of CVE-2026-61916 has not been confirmed. Its EPSS score was 0.2% on 2026-10-30, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-61916?

CVE-2026-61916 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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