CVE-2016-5825
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 · uneditedThe icalparser_parse_string function in libical 0.47 and 1.0 allows remote attackers to cause a denial of service (out-of-bounds heap read) via a crafted ics file.
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 heap-based out-of-bounds read vulnerability exists in libical's icalparser_parse_string function in versions 0.47 and 1.0. Attackers can trigger the vulnerability by providing a specially crafted ICS (iCalendar) file, causing the parser to read beyond allocated heap memory boundaries and leading to denial of service (crash).
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= 0.47= 1.0CVSS 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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/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 installed libical versionRun 'pkg-config --modversion libical' or check the library file version with 'dpkg -l libical*' (Debian) or 'rpm -qa | grep libical' (RHEL). Also check '/usr/lib/x86_64-linux-gnu/libical.so.*' or similar library path for the actual .so file version.Affected if The installed version is exactly 0.47 or 1.0, as these are the only affected versions listed.
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Determine if libical is in useSearch for processes or applications linking to libical by running 'ldd <application_binary>' or checking '/proc/<pid>/maps' for running processes. Common applications using libical include calendar clients like Evolution, Lightning, or server components like DavMail.Affected if Any application that links to the vulnerable libical library (0.47 or 1.0) is processing ICS data.
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Check for ICS file processingIdentify if any application accepts and parses ICS/iCalendar files. Look for file upload functionality, email attachment processing, or calendar synchronization features that ingest .ics files.Affected if The environment processes ICS files from any source, as the vulnerability triggers when icalparser_parse_string parses a specially crafted ICS file.
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Audit ICS input sourcesReview configuration for applications importing ICS data: check email gateways, calendar servers, or any service that accepts .ics attachments. Look for trust boundaries on who can submit ICS content.Affected if ICS files from untrusted or external sources can reach the libical parser, as this is the attack vector for the heap-based out-of-bounds read.
Your environment is affected if you are running libical version 0.47 or 1.0 and any application uses the icalparser_parse_string function to process ICS files from any source.
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 dataUpdate libical to the latest version containing the security patch. If immediate patching is not feasible, implement input validation to reject malformed ICS files from untrusted sources and restrict processing of ICS attachments from unknown senders.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-5825 — 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-2016-5825 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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