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Fencer Intel
medium 6.5

CVE-2026-105811 json

Authorization bypass through a user-controlled key in the Amazon Q Business Lambda hook sample in QnABot on AWS

published last mo. modified last mo. also EUVD-2026-93985

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 26%
public exploits
0
none known

Summary

Authorization bypass through a user-controlled key in the optional Amazon Q Business Lambda hook sample ( q-business-lambda-hook https://github.com/aws-solutions-library-samples/qnabot-on-aws/blob/main/source/docs/lambda_hooks/README.md ), available with QnABot on AWS versions 7.0.0 through 7.4.5, might allow an authenticated remote user to read arbitrary Amazon S3 objects in the deploying AWS account. This sample solution provides an example Lambda hook and requires separate, manual deployment and additional setup. It is not deployed automatically with QnABot. Customers who have not deployed this optional sample hook are not affected and do not need to take action.

To remediate this issue, affected customers should update the QnABot on AWS stack to version 7.4.6 or later and then redeploy the Amazon Q Business Lambda hook sample stack. Updating the QnABot on AWS stack alone does not deliver the fix.

Patch / fix

  • aws qnabot-on-aws 7.4.6

Is CVE-2026-105811 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 7.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA 4.0 7.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/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

Affected products

  • aws qnabot-on-aws

Classification

Weakness
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.