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Vulnerabilities

Security research · CVE-2026-78066

Apache bRPC: Resource Exhaustion via Unbounded Decompression and Unvalidated Wire-Declared Sizes

Published Oct 21, 2026 · catalog updated Oct 21, 2026 · Apache Software Foundation Apache bRPC

Last checked Oct 29, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-78066. EPSS is 0.16%. Act only if a listed version of Apache Software Foundation Apache bRPC is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Unknown—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.16%
Remediation
Version ranges on file
Affected products
stated named in the record · vendor Apache Software Foundation Apache bRPC

Resource exhaustion in Apache bRPC (version < 1.18.0) on all platforms: multiple parsers that accept wire-controlled input bound no limit on the sizes declared by the client or on decompressed output, which attackers can use to drive disproportionate memory use and crash the process. Root Cause: 1) The gzip/zlib/snappy decompressors enforce no output limit: -max_body_size is checked against the compressed bytes only, so a cap-compliant body (e.g. 64 MiB) can decompress to tens of GiB. 2) The AMF string readers allocate the declared length before the bytes are actually available. 3) RTMP chunk headers may re-declare a message length mid-stream; the declared length was never bounded and the partial reassembly buffer kept growing. 4) The sofa-pbrpc parser does not bound meta_size. 5) mcpack2pb trusts wire-declared item counts for Reserve() and a string value_size of 0 underflows the buffer size, aborting the process. Affected Scenarios: Any bRPC service accepting gzip/zlib/snappy-compressed bodies or rtmp, sofa-pbrpc, or mcpack2pb messages from untrusted clients. How to Fix:(Choose one of the following options) 1. Upgrade bRPC to version 1.18.0, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3476 Note: After the fix, requests whose decompressed size, RTMP message length, or mcpack declared count exceed the new limits are rejected. Operators who legitimately need larger values can raise the corresponding flag (-max_decompressed_body_size, max_body_size).

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.

  • stated named in the record< 1.18.0
  • vendor Apache Software Foundation Apache bRPCversion unspecified

How to fix CVE-2026-78066

What to do

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

Should you patch?

No confirmed exploitation is on record for CVE-2026-78066. EPSS is 0.16%. Act only if a listed version of Apache Software Foundation Apache bRPC is installed.

Which versions are affected?

Compare what you have installed with named in the record < 1.18.0. 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 0.16%. 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.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 21, 2026 · NIST NVD

    Detected

    Resource exhaustion in Apache bRPC (version < 1.18.0) on all platforms: multiple parsers that accept wire-controlled input bound no limit on the sizes declared by the client or on decompressed output, which attackers can use to drive disproportionate memory use and crash the process. Root Cause: 1) The gzip/zlib/snappy decompressors enforce no output limit: -max_body_size is checked against the co

Sources

  • CVE.orgVulnerability recordCVE-2026-78066

    Resource exhaustion in Apache bRPC (version < 1.18.0) on all platforms: multiple parsers that accept wire-controlled input bound no limit on the sizes declared by the client or on decompressed output, which attackers can use to drive disproportionate memory use and crash the proc

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-78066

    30-day exploitation probability 0.16%

    first.org
  • NIST NVDVulnerability recordCVE-2026-78066

    Resource exhaustion in Apache bRPC (version < 1.18.0) on all platforms: multiple parsers that accept wire-controlled input bound no limit on the sizes declared by the client or on decompressed output, which attackers can use to drive disproportionate memory use and crash the proc

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 29, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 23, 2026
  • CVE.orgOct 21, 2026
  • NIST NVDOct 21, 2026