CVE-2023-36841
Junos OS: MX Series: Receipt of malformed TCP traffic will cause a Denial of Service
- Published
- Updated
- Reserved
- Assigned by
- juniper
Description
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows a unauthenticated network-based attacker to cause an infinite loop, resulting in a Denial of Service (DoS). An attacker who sends malformed TCP traffic via an interface configured with PPPoE, causes an infinite loop on the respective PFE. This results in consuming all resources and a manual restart is needed to recover. This issue affects interfaces with PPPoE configured and tcp-mss enabled. This issue affects Juniper Networks Junos OS * All versions prior to 20.4R3-S7; * 21.1 version 21.1R1 and later versions; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S3; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3; * 22.3 versions prior to 22.3R2-S2; * 22.4 versions prior to 22.4R2;
Timeline
ID reserved
By juniper
- 4 months later
· 4 months later
Published
- 11 months later
· 11 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 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.62% · top 50% of all CVEs (7 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: High 7.5.
Weakness
Affected products
- affected < 20.4R3-S7
- affected 21.1R1 – < 21.1*
- affected 21.2 – < 21.2R3-S6
- affected 21.3 – < 21.3R3-S5
- affected 21.4 – < 21.4R3-S3
- affected 22.1 – < 22.1R3-S4
- affected 22.2 – < 22.2R3
- affected 22.3 – < 22.3R2-S2, 22.3R3
- affected 22.4 – < 22.4R2
What to do
Solution: The following software releases have been updated to resolve this specific issue: Junos OS 20.4R3-S7, 21.2R3-S6, 21.4R3-S3, 22.1R3-S4, 22.2R3, 22.3R2-S2, 22.3R3, 22.4R2, 23.2R1, and all subsequent releases.
Workaround: There are no known workarounds for this issue.
Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
References (1)
- https://supportportal.juniper.net/JSA73172 (opens in a new tab)vendor-advisoryx_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)
- 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://trackcve.app/cve/CVE-2023-36841)Record last updated .