CVE-2026-57022
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX with SPC3 and SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). When an affected device initiates a TCP connection to an attacker-controlled system that responds with a specific packet, this causes a PFE crash and restart, which affects all services until the system has automatically recovered. This issue can happen among others in the following scenarios: ALG, SSL proxy, UTM, RTLOG, AppQoE probing, AAMW, ICAP, URL filtering. This issue affects Junos OS on MX Series with SPC3, SRX5k Series with SPC3, SRX1600 Series, SRX2300 Series, SRX4000 Series, and vSRX Series: * all versions before 23.2R2-S4, * 23.4 versions before 23.4R2-S5, * 24.2 versions before 24.2R2.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA vulnerability in Juniper Networks Junos OS on MX with SPC3 and SRX Series allows an unauthenticated attacker to cause a Denial-of-Service by sending a specific packet in response to a TCP connection initiated by the affected device. This triggers a Packet Forwarding Engine (PFE) crash and restart, disrupting all services until automatic recovery.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 23.2= 23.2= 23.4= 24.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the device modelRun 'show chassis hardware' or check the physical device labeling to confirm it is a Juniper MX Series or SRX Series deviceAffected if The device is NOT an MX Series or SRX Series device (those are the only affected models)
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Confirm SPC3 presence on MX devicesFor MX Series, run 'show chassis hardware detail' or 'show chassis fpc' to identify the SPC3 (Services Processing Card 3) moduleAffected if The device is an MX Series WITHOUT SPC3 installed (only MX devices with SPC3 are affected)
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Check Junos OS versionRun 'show version' or 'show version invoke-on all-routing-engines' to display the installed Junos OS versionAffected if The installed version falls in these ranges: < 23.2, or exactly 23.2, or exactly 23.4, or exactly 24.2
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Verify TCP-based services are enabledRun 'show services sessions' or check if the device has configured protocols that initiate TCP connections (such as BGP, OSPF, management access, etc.)Affected if The device has TCP-based services or protocols configured and actively initiating connections (the attack requires the device to first initiate a TCP connection)
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Assess network exposureReview interface configurations with 'show configuration interfaces' and identify which interfaces connect to untrusted/external networksAffected if Any interface facing untrusted networks is active and reachable (attacker must be able to send packets in response to the device's TCP connection)
You are affected if you have an MX with SPC3 or SRX Series device running Junos OS versions 23.2, 23.4, or 24.2 (or any version before 23.2) with TCP services enabled and exposed to untrusted networks.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped23.2
Apply the vendor-supplied software updates (23.2R2-S4 and later, 23.4R2-S5 and later, 24.2R2 and later) to all affected devices. Prioritize devices exposed to untrusted networks.
23.2R2-S4 or later, 23.4R2-S5 or later, or 24.2R2 or later
- 1. Identify the current Junos OS version on the affected device using 'show version' command
- 2. Determine the appropriate upgrade path based on your current version branch (23.2, 23.4, or 24.2)
- 3. For devices on 23.2 branch: upgrade to 23.2R2-S4 or later
- 4. For devices on 23.4 branch: upgrade to 23.4R2-S5 or later
- 5. For devices on 24.2 branch: upgrade to 24.2R2 or later
- 6. Download the appropriate Junos OS upgrade image from the Juniper support portal
- 7. Upload the image to the device using 'file copy' or FTP/SCP
- 8. Install the upgrade using 'request system software add <package> reboot'
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-57022 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-57022 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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