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ImapApplication · Cyrus

CVE-2015-8077

HIGH · 7.5 CVSS v2.0 Published 2015-12-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable 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
Integer overflow in the index_urlfetch function in imap/index.c in Cyrus IMAP 2.3.19, 2.4.18, and 2.5.6 allows remote attackers to have unspecified impact via vectors related to urlfetch range checks and the start_octet variable. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-8076.

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 confidence

Integer overflow vulnerability in Cyrus IMAP's index_urlfetch function in imap/index.c. The flaw exists in urlfetch range check logic involving the start_octet variable, allowing remote attackers to cause unspecified impact via specially crafted requests. This CVE represents an incomplete fix of the earlier CVE-2015-8076.

MitigationUpgrade to Cyrus IMAP versions beyond 2.3.19, 2.4.18, and 2.5.6 that contain the complete fix. If immediate patching is not feasible, restrict unauthenticated network access to IMAP services.

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
ImapApplication
Affected:= 2.3.0= 2.3.1= 2.3.2= 2.3.3= 2.3.4= 2.3.5= 2.3.6= 2.3.7= 2.3.8= 2.3.9= 2.3.10= 2.3.11
LeapOperating system
Affected:= 42.1
OpensuseOperating system
Affected:= 13.2

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
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/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 checks

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

  1. Identify Cyrus IMAP installation and version
    Run 'cyrus --version' or check the package manager: 'rpm -q cyrus-imapd' (RHEL/CentOS) or 'dpkg -l | grep cyrus-imap' (Debian/Ubuntu). For SUSE, use 'rpm -q cyrus-imapd'
    Affected if The installed version is between 2.3.0 and 2.3.11 inclusive (exact versions: 2.3.0, 2.3.1, 2.3.2, 2.3.3, 2.3.4, 2.3.5, 2.3.6, 2.3.7, 2.3.8, 2.3.9, 2.3.10, 2.3.11)
  2. Confirm index module is enabled
    Check /etc/imapd.conf (or /etc/cyrus/imapd.conf) for configuration options related to indexing. Look for 'archive_after', 'archive_days', 'index_files', or 'archive_before' settings. Also check if the index module is loaded in the 'httpkeepalive' or 'httpmodules' directives if HTTP access is enabled.
    Affected if Index-related configuration options are present and the index feature is active (the vulnerable code path in index_urlfetch is exercised when index operations are performed)
  3. Check for HTTP-based URL fetching exposure
    If the HTTP gateway (httpd) is enabled, examine /etc/imapd.conf for 'httpkeepalive' and 'httpmodules' settings. The vulnerability is in the urlfetch function which can be triggered via HTTP requests.
    Affected if Cyrus IMAP is exposing HTTP-based IMAP or CalDAV/CardDAV services (the urlfetch function processes requests that include byte range parameters)
  4. Review server logs for anomalous urlfetch requests
    Examine Cyrus IMAP logs (typically /var/log/maillog or /var/log/imapd.log) for entries containing 'urlfetch' or 'index_urlfetch' with unusual byte range values, particularly very large start_octet values that could trigger integer overflow.
    Affected if Logs show urlfetch requests with extremely large start_octet values that exceed reasonable message sizes

A user is affected if they are running any Cyrus IMAP version from 2.3.0 through 2.3.11 with the index module enabled and network-accessible IMAP/HTTP services, as the integer overflow in index_urlfetch can be triggered via specially crafted byte range requests.

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 Cyrus IMAP versions beyond 2.3.19, 2.4.18, and 2.5.6 that contain the complete fix. If immediate patching is not feasible, restrict unauthenticated network access to IMAP services.

Fix this in Imap Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,120
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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-2015-8077 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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