GO-2026-5039 BIT-golang-2026-42507 CVE-2026-42507
Arbitrary inputs are included in errors without any escaping in net/textproto
- Severity
- 5.3 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.37%
- Chance of exploitation in the next 30 days. Higher than 30.99% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- —
- Not classified
- Fix
1.26.4- Upgrade stdlib to this version or later
Description
When returning errors, functions in the net/textproto package would include its input as part of the error. This might allow an attacker to inject misleading content to errors that are printed or logged.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| stdlib | < 1.25.11>= 1.26.0-0, < 1.26.4 |
1.25.111.26.4 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
stdlib Go → 1.26.4
- go
go get stdlib@v1.26.4 && go mod tidy
Severity breakdown
CVSS 3.1 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
References
Fixes and patches
Issue reports
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-4374-p667-p6c8 HTTP/2 rapid reset can cause excessive work in net/http | High Known exploited | Also affects stdlib |
| CVE-2020-0601 Certificate validation bypass on Windows in crypto/x509 | High Known exploited | Also affects stdlib |
| RUSTSEC-2026-0382 Distrust compromised intermediate certificates in crypto/x509 | Medium | Also affects stdlib |
| GO-2026-6613 HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http | High | Also affects stdlib |
| GO-2026-6609 Lack of limit on size of parsed Range headers in net/http | High | Also affects stdlib |
| GO-2026-6608 Memory limit bypass when parsing MIME headers in net/textproto, mime/multipart | High | Also affects stdlib |
| GO-2026-6607 Reject malformed ECH outer extension references in crypto/tls | High | Also affects stdlib |
| GO-2026-6604 Root.Mkdir(All) can follow junctions out of the root on Windows in os | Critical | Also affects stdlib |
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