CVE-2026-33818: Go standard library encoding/asn1 · Uncontrolled Resource Consumption
Affects Go standard library encoding/asn1Source CVE Database V5
Not known to be exploited · CVSS 7.5 High · fixed in 1.27.0-rc.3 : patch Go standard library encoding/asn1 soon.
Data as of 13 Nov 2026, 12:10 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 7.5 |
|---|
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.27.0-rc.3, 1.26.6, 1.25.13
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade Go standard library encoding/asn1 to 1.27.0-rc.3, 1.26.6 or 1.25.13.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Go standard libraryencoding/asn1 | Affected
| Fixed in
|
| Go standard libraryencoding/asn1 | Affected
| Fixed in
|
| Go standard libraryencoding/asn1 | Affected
| Fixed in
|
Goencoding/asn1pkg:golang/encoding/asn1Other threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to one of the fixed versions: 1.25.13, 1.26.6, or 1.27.0-rc.3. Applying these updates enforces a recursion limit in the Unmarshal function, preventing stack exhaustion. No other mitigation is indicated or required.
Description
CVE-2026-33818 is a high-severity vulnerability in the Go standard library's encoding/asn1 package. It involves uncontrolled resource consumption due to the lack of a recursion limit in the Unmarshal function, which can lead to stack exhaustion when parsing deeply nested or recursive ASN.1 structures. This flaw has been addressed in versions 1.25.13, 1.26.6, and 1.27.0-rc.3 of the Go standard library.