CVE
SOGo two-factor bypass by brute-forcing TOTP verification
Only affects SOGo before 5.12.13 with web login using TOTP two-factor verification. Fixed in 5.12.13.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 5.12.13
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 5.12.13.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.34% · 28th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 26/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
SOGo, the Alinto groupware product, contains a missing rate-limiting flaw in its web login two-factor (TOTP) verification step. An attacker who already knows a victim's password can reach it remotely, without logging in, and brute-force the second-factor code by repeatedly submitting guesses, since failed attempts never trigger a lockout, letting them bypass two-factor authentication.
Read the original description
SOGo before 5.12.13 contains a missing rate limiting vulnerability in its web login TOTP verification that allows attackers who already possess a victim's password to brute-force the second-factor code without triggering any lockout. Attackers can send repeated POST requests to /SOGo/connect with wrong verification codes at high speed since failed TOTP attempts never increment the failed-login counter and SOGoMaximumFailedLoginCount does not apply, enabling indefinite guessing across 30-second code windows to bypass two-factor authentication.
Who should check
Teams running Alinto SOGo before 5.12.13 with web login TOTP two-factor verification enabled.
Read the source excerpt
“SOGo before 5.12.13 contains a missing rate limiting vulnerability in its web login TOTP verification”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity9.1/10CVSS 9.1
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
- Would score about 31 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 5.12.13.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-127131 (SOGo before 5.12.13 Missing Rate Limiting on TOTP Verification), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-127131 (entry last updated 2026-11-12):
Affected:
- Alinto sogo: fixed in 5.12.13
Fixed versions: 5.12.13.
Conditions (all must be true for the bug to be hit):
- SOGo versions before 5.12.13 (source: https://www.vulncheck.com/advisories/sogo-before-missing-rate-limiting-on-totp-verification)
- Web login with TOTP two-factor verification in use (source: https://www.vulncheck.com/advisories/sogo-before-missing-rate-limiting-on-totp-verification)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-127131 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-127131 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/Alinto/sogo/releases/tag/SOGo-5.12.13
- https://www.vulncheck.com/advisories/sogo-before-missing-rate-limiting-on-totp-verification
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-127131
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-127131"}.Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- Alinto sogo
fixed in 5.12.13
Evidence 4
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-127131
Is CVE-2026-127131 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
SOGo's web login does not limit repeated attempts at the TOTP second-factor code, so the code can be brute-forced. An attacker who already holds the victim's password could then bypass two-factor authentication.Source: vulncheck.com
Which versions are affected by CVE-2026-127131?
sogo: before 5.12.13.Source: cve.now feed data
Am I affected, and how do I check?
SOGo versions before 5.12.13 are listed as affected, and the issue applies when web login uses TOTP two-factor verification. To check, look at the installed SOGo version and whether TOTP is enabled for web login in the server configuration.Source: vulncheck.com
How do I fix CVE-2026-127131?
Upgrade SOGo to 5.12.13 or later, which is the listed fixed version.Source: vulncheck.com