Session And Resource ControlApplication · Juniper

CVE-2021-31352

MEDIUM · 5.3 CVSS v3.1 Published 2021-10-19
Fix available
A fix is available. Upgrade to 4.130r6 or later.
See remediation →
62/100
Remediation priority · Elevated
Public exploit Remotely reachable No privileges Zero-click Patch available

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 · unedited
An Information Exposure vulnerability in Juniper Networks SRC Series devices configured for NETCONF over SSH permits the negotiation of weak ciphers, which could allow a remote attacker to obtain sensitive information. A remote attacker with read and write access to network data could exploit this vulnerability to display plaintext bits from a block of ciphertext and obtain sensitive information. This issue affects all Juniper Networks SRC Series versions prior to 4.13.0-R6.

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
How this class of weakness works · CWE-200

The application discloses data — error detail, internal paths, tokens, or other users' records — to someone who shouldn't see it. On its own it can look minor, but it hands attackers the map they need for a larger attack. Remediation is about minimising what's returned and enforcing authorization on every piece of data.

General guidance for the information exposure class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
Session And Resource ControlApplication
Affected:< 4.130r6

CVSS 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
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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 · scoped
Upgrade available Upgrade to 4.130r6 or later
Fixed in 4.130r6
Vendor patch kb.juniper.net →
Recommended fix Moderate confidence

4.13.0-R6 (or later)

  1. 1. Review current SRC Series device configuration and document existing settings
  2. 2. Download the Juniper Networks SRC Series software version 4.13.0-R6 or later from the Juniper Networks support portal
  3. 3. Schedule a maintenance window to minimize operational impact
  4. 4. Back up the current device configuration
  5. 5. Upgrade the device to version 4.13.0-R6 or later using the Juniper Networks upgrade procedure
  6. 6. Verify the NETCONF over SSH configuration and confirm weak ciphers are no longer negotiable
  7. 7. Test that normal SRC Series operations function correctly post-upgrade
Caveat Review Juniper Networks release notes for any configuration changes or deprecations between your current version and 4.13.0-R6

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $900. Get the upgrade done

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-31352 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data