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CVE.org (no NVD analysis yet)· CNA Secur0

CVE-2026-121564: Silent loss of messages when merging overlapping chat exports in whatstk

LowCVSS 1.8 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 7/100)

  • 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: 0.34% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: lucasrodes whatstk 0.9.0.

Low priority for now. Upgrade to lucasrodes whatstk 0.9.0 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

Incomplete Comparison with Missing Factors (CWE-1023) in merge_chats() (whatstk/utils/chat_merge.py), reached from BaseChat.merge(), in whatstk from 0.3.0 before 0.9.0 allows a party that supplies the chat exports to cause messages to be absent from the merged output with no indication that anything was removed, because the merge keeps whole the chat whose first message is oldest and appends from the other only the messages that are strictly newer than the last message of the first. Every message of the second chat that falls inside the date range already covered by the first is therefore discarded. The two chats are compared on their date ranges and not on the identity of the individual messages, so a message held by only one of the two exports is dropped whenever its date falls inside the range of the other, and both branches of _merge_two_chats() behave this way. The merged result is returned without a warning and without a count of what was removed. This results in a merged chat that omits messages the inputs contain, in a library whose documented uses include forensic review and the generation of training data.

Published
Nov 3, 2026
Updated
Nov 3, 2026
EPSS
0.3% · 27th percentile

Report tools

JSON

Action score

7

Monitor

Low priority for now.

CVSS
7 / 40 · 1.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Secur0
1.8
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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

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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?

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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 (Secur0). Independent of NVD's CPE analysis and usually ahead of it.

  • lucasrodes whatstk

    • 0.3.0 and later · before 0.9.0affected · semver

Same product

lucasrodes: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-121691Unbounded decompression in the whatstk ZIP loader exhausts memory and disk
    26Monitor
  • CVE-2026-121577Unescaped header separators in whatstk build a regular expression that backtracks exponentially
    26Monitor

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
lucasrodes whatstk0.9.0Vendor (CNA)

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 recordedsame day
  3. TodayNov 13, 2026+10 d
EPSS, last 120 days

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

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

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

Not on record for this CVE: variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
A
Scope
X

Weakness class (CWE)

CWE-1023 · Incomplete Comparison with Missing Factors

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Exploit maturity— → none
  3. Fix✗ → ✓

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

References

Show all references (3 more)

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

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