CVE-2024-21607Junos OS: MX Series and EX9200 Series: If the "tcp-reset" option used in an IPv6 filter, matched packets are accepted instead of rejected
- 5.3MediumCVSS base score
- 0.31%Exploitation in 30 daysEPSS · top 76% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
An Unsupported Feature in the UI vulnerability in Juniper Networks Junos OS on MX Series and EX9200 Series allows an unauthenticated, network-based attacker to cause partial impact to the integrity of the device. If the "tcp-reset" option is added to the "reject" action in an IPv6 filter which matches on "payload-protocol", packets are permitted instead of rejected. This happens because the payload-protocol match criteria is not supported in the kernel filter causing it to accept all packets without taking any other action. As a fix the payload-protocol match will be treated the same as a "next-header" match to avoid this filter bypass. This issue doesn't affect IPv4 firewall filters. This issue affects Juniper Networks Junos OS on MX Series and EX9200 Series: * All versions earlier than 20.4R3-S7; * 21.1 versions earlier than 21.1R3-S5; * 21.2 versions earlier than 21.2R3-S5; * 21.3 versions earlier than 21.3R3-S4; * 21.4 versions earlier than 21.4R3-S4; * 22.1 versions earlier than 22.1R3-S2; * 22.2 versions earlier than 22.2R3-S2; * 22.3 versions earlier than 22.3R2-S2, 22.3R3; * 22.4 versions earlier than 22.4R1-S2, 22.4R2-S2, 22.4R3.
Timeline
ID reserved
By juniper
- 16 days later
· 16 days later
Published
- 17 months later
· 17 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| juniperCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.31% · top 76% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Affected products
- affected < 20.4R3-S7
- affected 21.1 – < 21.1R3-S5
- affected 21.2 – < 21.2R3-S5
- affected 21.3 – < 21.3R3-S4
- affected 21.4 – < 21.4R3-S4
- affected 22.1 – < 22.1R3-S2
- affected 22.2 – < 22.2R3-S2
- affected 22.3 – < 22.3R2-S2, 22.3R3
- affected 22.4 – < 22.4R1-S2, 22.4R2-S2, 22.4R3
What to do
Solution: The following software releases have been updated to resolve this specific issue: Junos OS 20.4R3-S7, 21.1R3-S5, 21.2R3-S5, 21.3R3-S4, 21.4R3-S4, 22.1R3-S2, 22.2R3-S2, 22.3R2-S2, 22.3R3, 22.4R1-S2, 22.4R2-S2, 22.4R3, 23.2R1, and all subsequent releases.
Workaround: A workarounds is to replace the payload-protocol match with a next-header match like in the following example: [ firewall family inet6 filter <filter name> term <term name> match next-header] [ firewall family inet6 filter <filter name> term <term name> then reject tcp-reset ]
Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
References
References2
- https://supportportal.juniper.net/JSA75748 (opens in a new tab)vendor-advisoryx_transferred
- https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N (opens in a new tab)technical-descriptionx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2024-19255 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2024-21607)Record last updated .