# CVE-2026-94440: Go memory limit bypass in MIME header parsing

Source: https://junglewise.ai/threats/cve-2026-94440-go-2026-6608-memory-limit-bypass-when-parsing-mime-headers-in-net  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-08. Updated: 2026-10-10  
License: CC BY 4.0 with a link back

CVE-2026-94440 · Severity: high · CVSS 7.5 · Published 2026-10-08

Go's net/textproto and mime/multipart libraries, used to parse email-style headers and multipart form data, can be bypassed to read arbitrarily long data into memory. An attacker sending a crafted multipart form request could exhaust server memory, causing denial of service on applications that rely on these limits for protection.

Technologies: [go (Go)](https://junglewise.ai/threats/technologies/go), [stdlib (Go)](https://junglewise.ai/threats/technologies/go-stdlib). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-94440 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-94440 being exploited in the wild.

**How severe is CVE-2026-94440?** High severity, with a CVSS score of 7.5, published 8 October 2026.

**Which products and versions are affected?** go (Go) versions prior to the fix in Go 1.28; stdlib (Go) SEMVER:introduced=0,fixed=1.26.9,introduced=1.27.0-0,fixed=1.27.2.

**Is there a fix for CVE-2026-94440?** Yes. stdlib (Go): upgrade to 1.27.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-94440 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-94440?** Check whether you run go (Go) or stdlib (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- stdlib (Go): upgrade to 1.27.2 or later

  ```sh
  go get stdlib@v1.27.2
  ```


## Technical details

When parsing multipart forms, the memory limit enforcement fails if the remaining byte limit at the start of a part is less than 400 bytes, allowing an attacker to bypass the limit and read an arbitrarily long line into memory. The vulnerability is in net/textproto and mime/multipart packages. A fix has been implemented and committed.

## Affected products

- Go Go versions prior to the fix in Go 1.28

## Identifiers

- CVE-2026-94440
- GO-2026-6608

## Timeline

- 2026-09-24: disclosed: Issue reported and privately tracked
- 2026-10-08: advisory: Public advisory published as GO-2026-6608

## References

- [https://go.dev/cl/847307](https://go.dev/cl/847307)
- [https://go.dev/issue/81741](https://go.dev/issue/81741)

## Related threats

- [Go HTTP/1 server race condition in MaxBytesReader header handling](https://junglewise.ai/threats/cve-2026-97054-for-http-1-servers-when-maxbytesreader-s-limit-is-exceeded)
- [Go command unsafe pkg-config flag handling in cgo](https://junglewise.ai/threats/cve-2026-97039-building-a-malicious-package-that-uses-cgo-pkg-config-directives)
- [Go linker code injection via malicious package compilation](https://junglewise.ai/threats/cve-2026-97038-building-a-malicious-package-containing-syso-files-or-cgo-linker)
- [Go arbitrary code execution via malicious cgo linker flags](https://junglewise.ai/threats/cve-2026-97037-building-a-malicious-package-that-uses-cgo-could-cause-arbitrary)
- [Go cgo arbitrary code execution via Apple linker argument injection](https://junglewise.ai/threats/cve-2026-97036-on-darwin-building-a-malicious-package-that-uses-cgo-could-cause)