🛡️ CVE-2026-33811 — go
Description
Crash when handling long CNAME response in net
When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.
How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector: Network — reachable from anywhere that can route to the service.
- Attack complexity: Low — the attack works reliably, with no preparation.
- Privileges required: None — an unauthenticated stranger can try it.
- User interaction: None — nobody has to be tricked into anything.
- Scope: Unchanged — the damage stays inside the vulnerable component.
- Confidentiality impact: None.
- Integrity impact: None.
- Availability impact: High — total loss, or loss the attacker controls.
Weakness class
CVE-2026-33811 is classified as CWE-415: Double Free. The same allocation is released twice, corrupting allocator bookkeeping.
Affected software
CVE-2026-33811 is recorded against 3 packages.
- go (from 1.26.0 up to 1.26.3)
- golang
- stdlib
Timeline and source
Published on 7 May 2026 and last revised on 18 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.
References
go.dev
go.dev
groups.google.com
pkg.go.dev
access.redhat.com
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Other advisories for this package
go has other advisories on record. If you are patching this one, these are worth checking on the same host:
- BELL-CVE-2026-39822 (published 11 Jul 2026)
- BELL-CVE-2026-42505 (published 10 Jul 2026)
- CVE-2026-42505 (5.3 Medium, published 8 Jul 2026)
- CVE-2026-39822 (7.8 High, published 8 Jul 2026)
- CVE-2023-54365 (7.5 High, published 23 Jun 2026)
- BELL-CVE-2026-42507 (published 5 Jun 2026)
- BELL-CVE-2026-42504 (published 5 Jun 2026)
- BELL-CVE-2026-27145 (published 5 Jun 2026)
Same weakness in other software
These advisories are the same class of weakness (CWE-415: Double Free) in other software:
- CVE-2023-25801 (8.0 High, published 13 Jul 2026)
- CVE-2025-12343 (3.3 Low, published 18 Feb 2026)
- CVE-2025-13844 (5.3 Medium, published 15 Jan 2026)
- CVE-2025-47356 (7.8 High, published 7 Jan 2026)
- CVE-2025-47396 (7.8 High, published 7 Jan 2026)
- CVE-2025-20786 (6.7 Medium, published 6 Jan 2026)
- CVE-2025-20781 (7.8 High, published 6 Jan 2026)
- CVE-2025-20801 (7.0 High, published 6 Jan 2026)
CVE-2026-33811 on other distributions
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| go | 1.26.0 | 1.26.3 |
| golang | — | — |
| stdlib | — | — |
References
Similar Threats
- Unknown BELL-CVE-2024-24789
- Unknown BELL-CVE-2024-24790
- Unknown BELL-CVE-2024-24788
- Unknown BELL-CVE-2023-45288
- Unknown BELL-CVE-2023-45289
Site Security Check
Is go part of your stack?
CVE-2026-33811 is rated CVSS 8.0 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.
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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.
