CVE-2016-5826
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 parser_get_next_char function in libical 0.47 and 1.0 allows remote attackers to cause a denial of service (out-of-bounds heap read) by crafting a string to the icalparser_parse_string function.
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 parser_get_next_char function (versions 0.47 and 1.0). When parsing a specially crafted string through icalparser_parse_string, the parser reads beyond buffer boundaries on the heap, causing denial of service.
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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/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 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 | grep libical' (Debian) or 'rpm -q libical' (RHEL). Alternatively, check the SO library version in /usr/lib/ with 'ls -la libical*'Affected if The installed version is exactly 0.47 or 1.0
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Verify the application links against libicalUse 'ldd <application_binary>' or 'ldd <shared_library>' to see if libical is linked. Also check build files (Makefile, CMakeLists.txt) for -lical linker flagAffected if The application or library depends on libical
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Determine if icalparser_parse_string is calledSearch source code with 'grep -r "icalparser_parse_string"' or inspect binary with 'nm <binary> | grep icalparser_parse_string' or 'objdump -T <binary> | grep icalparser_parse_string'Affected if The code calls icalparser_parse_string to parse iCalendar data
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Check if untrusted iCalendar input reaches the parserReview the data flow: trace where iCalendar data originates (file upload, network input, external API) and whether it is validated before passing to icalparser_parse_string. Search for validation routines with 'grep -r "icalparser_parse_string"' and review the call chainAffected if Unsanitized or unvalidated iCalendar data from external sources is passed to icalparser_parse_string
You are affected if you run libical version 0.47 or 1.0 and your application passes untrusted iCalendar input to the icalparser_parse_string function without prior validation.
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 a patched version. Until then, sanitize and validate all iCalendar input before passing to icalparser_parse_string to prevent processing of maliciously crafted data.
- Consultation2.0 h
- Implementation4.0 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 $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-5826 — 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-2016-5826 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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