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CVE.org (no NVD analysis yet)· CNA mozilla

CVE-2026-118177: Calendar discovery accepted local file and remote network share locations

CriticalCVSS 9.1 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.45% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: thunderbird (Debian:12) 1:153.6.0esr-1~deb12u2; thunderbird (Debian:13) 1:153.6.0esr-1~deb13u1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to thunderbird (Debian:12) 1:153.6.0esr-1~deb12u2; thunderbird (Debian:13) 1:153.6.0esr-1~deb13u1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

When looking for calendars in a directory on a server, during account setup or when adding a new network calendar, Thunderbird accepted calendar locations pointing to other servers, local files or network shares. A malicious server, or a network attacker when the lookup used plain HTTP, could make Thunderbird subscribe to such a location. On Windows this could leak the user's NTLM credentials to an attacker-controlled host on every calendar refresh, and changes to the calendar could be written to the attacker's share or overwrite a local file. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

Published
Oct 27, 2026
Updated
Nov 4, 2026
EPSS
0.4% · 39th percentile

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-118177

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (mozilla). Independent of NVD's CPE analysis and usually ahead of it.

  • Mozilla Thunderbird

    • 153.6 and later · up to and including 153.*not affected · rpm
    • 159 and laternot affected · rpm

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12thunderbirdbefore 1:153.6.0esr-1~deb12u21:153.6.0esr-1~deb12u2
Debian:13thunderbirdbefore 1:153.6.0esr-1~deb13u11:153.6.0esr-1~deb13u1
Debian:14thunderbirdfrom 0—

Same product

mozilla: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-11705A flaw in Thunderbird's implementation of iCal causes a stack buffer overflow in icalrecur_add_bydayrules when processing certain email…
    42Plan
  • CVE-2019-11704A flaw in Thunderbird's implementation of iCal causes a heap buffer overflow in icalmemory_strdup_and_dequote when processing certain email…
    42Plan
  • CVE-2019-11703A flaw in Thunderbird's implementation of iCal causes a heap buffer overflow in parser_get_next_char when processing certain email…
    42Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-118175Oct 27, 2026 · Content of other messages could be included when replying to a crafted message
    30Monitor
  • ← EarlierCVE-2026-118176Oct 27, 2026 · Bypass of remote UNC path restriction in mailbox: URLs
    32Monitor
  • Later →CVE-2026-118178Oct 27, 2026 · RSS feed could redirect its subscription to a local file or network share
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:thunderbird1:153.6.0esr-1~deb12u2 · Debian:12Package registry (OSV)
debian:thunderbird1:153.6.0esr-1~deb13u1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recorded+3 d
  3. TodayNov 13, 2026+17 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-1181800 days apartMatrix homeserver could redirect the chat session to a local file or network share
    30Monitor

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Not on record for this CVE: patch commit or PR link · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-601 · URL Redirection to Untrusted Site ('Open Redirect')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. CVSS— → 9.1
  2. Severity— → critical
  3. SSVC exploitation— → none
  4. Fix✗ → ✓
  5. Exploit maturity— → none

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records