- Exploited
- No known exploitation
- Fix
- Fixed in 1.26.11, 1.27.4
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 1.26.11, 1.27.4.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 10/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Go standard library's net/http package, used by HTTP/1 servers, can crash when a server's handler uses MaxBytesReader or MaxBytesHandler and reads the request body while also writing the response header. The crash is a runtime panic caused by an unsynchronized "Connection: close" header update, and the vulnerability's CVSS and attacker-access details are not provided, so the reach is not stated.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach10/20Affects Go packages
- Severity?/10Unknown. No CVSS score or vendor rating
- No patch0/5No signal
What would change the score
- Would score about 65 if added to CISA KEV
- Would score about 60 if CISA's SSVC rates exploitation active
- Would score about 32 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 1.26.11, 1.27.4.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-97054 (HTTP/1 server crash due to MaxBytesReader header race in net/http), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-97054 (entry last updated 2026-11-11): Affected: - Go package net/http: fixed in 1.26.11; from 1.27.0-0, fixed in 1.27.4 - Go package stdlib: fixed in 1.26.11; from 1.27.0-0, fixed in 1.27.4 Fixed versions: 1.26.11, 1.27.4. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-97054 is not listed as of cve.now's last read. This KEV status is for CVE-2026-97054 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Packages (Go): find every lockfile in each project and run check_stack from the cve.now MCP server on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies. Verify against the linked advisories before concluding, and cite the date you read each one: - https://go.dev/cl/862185 - https://go.dev/issue/82563 - https://groups.google.com/g/golang-announce/c/iY8TY0wWgbM - https://pkg.go.dev/vuln/GO-2026-6859 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-97054 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-97054.
Timeline
- CVE published
- First seen by cve.now
Affected versions
Evidence 5
Other links · 4
- Link
- Link
- Link
- Link
Corrections
None so far.
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Questions about CVE-2026-97054
Is CVE-2026-97054 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-97054?
net/http (Go): before 1.26.11; from 1.27.0-0 before 1.27.4. stdlib (Go): before 1.26.11; from 1.27.0-0 before 1.27.4.Source: cve.now feed data
How do I fix CVE-2026-97054?
Upgrade to a fixed version: 1.26.11, 1.27.4.Source: cve.now feed data