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Debian LinuxOperating system · Debian

CVE-2012-5521

MEDIUM · 6.5 CVSS v3.1 Published 2019-11-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
No privileges Zero-click

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
quagga (ospf6d) 0.99.21 has a DoS flaw in the way the ospf6d daemon performs routes removal

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 · moderate confidence

A denial of service vulnerability exists in quagga's ospf6d daemon version 0.99.21 in how it handles route removal operations. The flaw can cause the OSPFv3 routing daemon to crash or become unresponsive when processing certain route removal scenarios, disrupting routing services.

MitigationUpgrade to a patched version of quagga beyond 0.99.21, or apply vendor-supplied security patches. Restrict OSPFv3 peer access to trusted sources to reduce attack surface until patching is completed.

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
Debian LinuxOperating system
Affected:= 8.0= 9.0= 10.0
Enterprise LinuxOperating system
Affected:= 5.0= 6.0
QuaggaApplication
Affected:= 0.99.21

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/AC:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify quagga is installed
    Check for quagga package using package manager: dpkg -l | grep quagga (Debian/RHEL) or rpm -qa | grep quagga
    Affected if quagga package is present on the system
  2. Check ospf6d daemon is running
    Run 'ps aux | grep ospf6d' or 'systemctl status ospf6d' to see if the OSPFv3 daemon process is active
    Affected if ospf6d process is running
  3. Determine installed quagga version
    Run 'quagga -v' or check package version: dpkg -l quagga or rpm -q quagga
    Affected if installed version equals 0.99.21 exactly
  4. Confirm OSPFv3 routing is configured
    Check for ospf6d configuration in /etc/quagga/ospf6d.conf or /etc/quagga/ and verify OSPFv3 interfaces are defined in the config
    Affected if OSPFv3 is actively configured and in use

A system is affected if quagga version 0.99.21 is installed and the ospf6d daemon is running with OSPFv3 configured.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to a patched version of quagga beyond 0.99.21, or apply vendor-supplied security patches. Restrict OSPFv3 peer access to trusted sources to reduce attack surface until patching is completed.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,900
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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-2012-5521 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
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