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Fencer Intel
no cvss —

CVE-2026-97054 json

HTTP/1 server crash due to MaxBytesReader header race in net/http

published yesterday modified yesterday also EUVD-2026-123113 , GO-2026-6859

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

For HTTP/1 servers, when MaxBytesReader's limit is exceeded, "Connection: close" header is automatically set without synchronization, which might race with another header being set explicitly in the server handler. As a result, an HTTP/1 server that utilizes MaxBytesReader or MaxBytesHandler can crash due to runtime panic if its handler reads the request body concurrently with writing the response header.

Patch / fix

  • go stdlib 1.26.11, 1.27.4
  • Go standard library net/http 1.26.11, 1.27.4

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Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-11).

Affected packages

ecosystem package affected fixed in
go stdlib
<1.26.11
>=1.27.0-0, <1.27.4
1.26.11
1.27.4

Affected products

  • Go standard library net/http

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.