Linux KernelOperating system · Linux
CVE-1999-0257
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 · uneditedNestea variation of teardrop IP fragmentation denial of service.
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 confidenceThe Nestea attack is a variant of the teardrop attack that exploits vulnerabilities in IP fragment reassembly. It sends specially crafted, overlapping IP fragments that cause the target system's network stack to crash or become unresponsive when attempting to reassemble malformed packets.
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
Linux KernelOperating system
= 2.6.20.1CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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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Check the running Linux kernel versionRun 'uname -r' or 'cat /proc/version' to display the kernel versionAffected if The version is exactly 2.6.20.1
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Verify IP fragment reassembly capabilityCheck kernel configuration with 'cat /boot/config-$(uname -r) | grep -i fragment' or check if /proc/sys/net/ipv4/ipfrag* settings existAffected if IP fragment reassembly is enabled in the kernel configuration
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Check for crash logs related to IP fragmentationReview system logs with 'dmesg' or check /var/log/messages for kernel panics or oops messages mentioning 'fragment' or 'IP' reassembly errorsAffected if Recent crash logs show IP fragment reassembly failures or kernel crashes matching the attack signature
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Verify network stack is processing IPv4 fragmentsMonitor network traffic with 'tcpdump -i any ip[6:2] & 0x3fff != 0' to capture fragmented packets, or check 'ip -s link' for fragment statisticsAffected if The system is receiving and processing IPv4 fragmented packets on network interfaces
A defender is affected if their system runs Linux Kernel 2.6.20.1 with IP fragment reassembly enabled and is exposed to untrusted network traffic containing specially crafted overlapping fragments.
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.
From vendor dataApply operating system patches that address IP fragment reassembly vulnerabilities, or deploy network filtering (firewalls/IDS) at the perimeter to detect and block malformed overlapping fragments.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-1999-0257 — 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-1999-0257 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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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.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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