Summary
An Out-of-bounds Read vulnerability in Juniper Networks Junos OS and Junos OS Evolved's routing...
An Out-of-bounds Read vulnerability in Juniper Networks Junos OS and Junos OS Evolved's routing protocol daemon (rpd) allows an unauthenticated, network-based attacker to send malformed BGP packets to a device configured with packet receive trace options enabled to crash rpd.
This issue affects:
Junos OS:
- from 21.2R3-S8 before 21.2R3-S9,
- from 21.4R3-S7 before 21.4R3-S9,
- from 22.2R3-S4 before 22.2R3-S5,
- from 22.3R3-S2 before 22.3R3-S4,
- from 22.4R3 before 22.4R3-S5,
- from 23.2R2 before 23.2R2-S2,
- from 23.4R1 before 23.4R2-S1,
- from 24.2R1 before 24.2R1-S1, 24.2R2.
Junos OS Evolved:
- from 21.4R3-S7-EVO before 21.4R3-S9-EVO,
- from 22.2R3-S4-EVO before 22.2R3-S5-EVO,
- from 22.3R3-S2-EVO before 22.3R3-S4-EVO,
- from 22.4R3-EVO before 22.4R3-S5-EVO,
- from 23.2R2-EVO before 23.2R2-S2-EVO,
- from 23.4R1-EVO before 23.4R2-S1-EVO,
- from 24.2R1-EVO before 24.2R1-S2-EVO, 24.2R2-EVO.
This issue requires a BGP session to be established.
This issue can propagate and multiply through multiple ASes until reaching vulnerable devices.
This issue affects iBGP and eBGP.
This issue affects IPv4 and IPv6.
An indicator of compromise may be the presence of malformed update messages in a neighboring AS which is unaffected by this issue:
For example, by issuing the command on the neighboring device:
show log messages
Reviewing for similar messages from devices within proximity to each other may indicate this malformed packet is propagating:
rpd[]: Received malformed update from (External AS <AS#>)
and
rpd[]: Malformed Attribute
Impact
A read operation accesses a memory location beyond the intended buffer boundary. Typical impact: sensitive data disclosure or crash.
CVE-2025-21598 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-21598? CVE-2025-21598 is a high-severity out-of-bounds read vulnerability. No fixed version is listed yet. A read operation accesses a memory location beyond the intended buffer boundary.
- How severe is CVE-2025-21598? CVE-2025-21598 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-21598? No fixed version is listed for CVE-2025-21598 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-21598 exploitable, and should I be worried? Whether CVE-2025-21598 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-21598 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.