CVE-2021-45485
A public proof of concept exists; no exploitation attested.
- Published2021-12-25
- Fixed in5.13.3 · 5.12.18 · 5.10.51 · 5.4.133 · 4.19.198 · 4.14.240
- WeaknessCWE-327
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
In the IPv6 implementation in the Linux kernel before 5.13.3, net/ipv6/output_core.c has an information leak because of certain use of a hash table which, although big, doesn't properly consider that IPv6-based attackers can typically choose among many IPv6 source addresses.
Timeline
dates in UTC- 2021-12-2502:15CVE publishedNVD
- 2026-10-2319:23First public proof of conceptPoC-in-GitHub
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-45485?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-45485?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 5.13 | ≥ 5.13, < 5.13.3 | 5.13.3 | NVD |
| 5.x | ≥ 5.11, < 5.12.18 | 5.12.18 | NVD |
| 5.x | ≥ 5.5, < 5.10.51 | 5.10.51 | NVD |
| 5.4 | ≥ 4.20, < 5.4.133 | 5.4.133 | NVD |
| 4.x | ≥ 4.15, < 4.19.198 | 4.19.198 | NVD |
| 4.x | ≥ 4.10, < 4.14.240 | 4.14.240 | NVD |
| 4.x | ≥ 4.5, < 4.9.276 | 4.9.276 | NVD |
| 4.4 | < 4.4.276 | 4.4.276 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| — | all versions | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| — | all versions | no fix published | NVD |
23 more products in the sources.
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Packages
- kernelAlmaLinux:8all versions · fixed in 4.18.0-372.9.1.el8and 19 other packages
Fix
- Update Linux linux kernel to 5.13.3 · 5.12.18 · 5.10.51 · 5.4.133 · 4.19.198 · 4.14.240 · 4.9.276 · 4.4.276
Advisories and patches
- cdn.kernel.orgRelease Notes · Vendor Advisory
- git.kernel.orgPatch · Vendor Advisory
- www.oracle.comPatch
Detection
read 2026-10-23 19:23 UTC- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- 1 repository, unverifiedSatheesh575555/linux-4.19.72_CVE-2021-45485 PoC-in-GitHub
Sources
- NVDCVSS 3.17.5read 2026-10-23
- NVDCVSS 2.05read 2026-10-23
- NVDweakness (CWE)CWE-327read 2026-10-23
- FIRST EPSSEPSS score3.8 %2026-10-23
- PoC-in-GitHubproof of concept1read 2026-10-23
- OSVaffected packages—
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Published
- 2021-12-25
- Last Modified
- 2026-08-05
- NVD status
- Analyzed
Frequently asked questions
What is CVE-2021-45485?
Is CVE-2021-45485 actively exploited?
What is the CVSS score for CVE-2021-45485?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.