CVE-2021-20322
A flaw in the processing of received ICMP errors (ICMP fragment needed and ICMP redirect) in the Linux kernel functionality was found to allow the ability to quickly scan open UDP ports.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (6.90%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A flaw in the processing of received ICMP errors (ICMP fragment needed and ICMP redirect) in the Linux kernel functionality was found to allow the ability to quickly scan open UDP ports. This flaw allows an off-path remote user to effectively bypass the source port UDP randomization. The highest threat from this vulnerability is to confidentiality and possibly integrity, because software that relies on UDP source port randomization are indirectly affected as well.
- CVSS 3.1
- 7.4 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 6.90% probability · 94th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-330
- Affected
- linux/linux kernel · fedoraproject/fedora · debian/debian linux · netapp/active iq unified manager · netapp/e-series santricity os controller · netapp/solidfire\, enterprise sds \& hci storage node · netapp/solidfire \& hci management node · netapp/fas baseboard management controller firmware · netapp/aff baseboard management controller firmware · netapp/aff a700s firmware · netapp/h700s firmware · netapp/h700e firmware · netapp/h500s firmware · netapp/h410s firmware · netapp/h500e firmware · netapp/h300e firmware · netapp/h300s firmware · netapp/hci compute node firmware · oracle/communications cloud native core binding support function · oracle/communications cloud native core network exposure function · +1 more
- Source
- secalert@redhat.com
EPSS 6.9% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=2014230Issue Tracking, Third Party Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.15-rc6&id=4785305c05b25a242e5314cc821f54ade4c18810Mailing List, Patch, Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.15-rc6&id=6457378fe796815c973f631a1904e147d6ee33b1Mailing List, Patch, Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/ipv4/route.c?h=v5.15-rc6&id=67d6d681e15b578c1725bad8ad079e05d1c48a8eMailing List, Patch, Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/ipv6/route.c?h=v5.15-rc6&id=a00df2caffed3883c341d5685f830434312e4a43Mailing List, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.htmlMailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20220303-0002/Third Party Advisory
- https://www.debian.org/security/2022/dsa-5096Third Party Advisory
- https://www.oracle.com/security-alerts/cpujul2022.htmlThird Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2014230Issue Tracking, Third Party Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.15-rc6&id=4785305c05b25a242e5314cc821f54ade4c18810Mailing List, Patch, Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.15-rc6&id=6457378fe796815c973f631a1904e147d6ee33b1Mailing List, Patch, Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/ipv4/route.c?h=v5.15-rc6&id=67d6d681e15b578c1725bad8ad079e05d1c48a8eMailing List, Patch, Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/ipv6/route.c?h=v5.15-rc6&id=a00df2caffed3883c341d5685f830434312e4a43Mailing List, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.htmlMailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20220303-0002/Third Party Advisory
- https://www.debian.org/security/2022/dsa-5096Third Party Advisory
- https://www.oracle.com/security-alerts/cpujul2022.htmlThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.