Remark42: Rate limit bypass via unconditional trust of X-Forwarded-For/X-Real-IP headers in direct-internet deployment
- Exploited
- No known exploitation
- Fix
- Fixed in 1.16.2
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 1.16.2.
- Last modified
- 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? →
- 24/100 · provisional
- 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
Remark42, a self-hosted comment engine, trusts client-supplied forwarding headers (X-Forwarded-For, X-Real-IP, and True-Client-IP) without checking that the request comes from a trusted proxy. A remote attacker with no login can use this to evade rate limits, bypass vote de-duplication, create anonymous identities, and falsify stored comment IP addresses and request logs.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
Remark42 is a self-hosted comment engine for blogs, articles, or any other place where readers can add comments. From 1.0.0 until 1.16.2, Remark42 globally trusts True-Client-IP, X-Real-IP, and X-Forwarded-For without verifying that the direct peer is a trusted proxy, and middleware.RealIP overwrites r.RemoteAddr before per-IP controls run. In a directly reachable deployment, or a proxy that forwards attacker-controlled headers, a remote attacker can rotate spoofed forwarding headers to obtain fresh token buckets for rate-limited endpoints, bypass vote de-duplication when --votes-ip is enabled, mint anonymous identities, and poison stored comment IPs and request logs. The global concurrent-request throttle and per-request timeouts still limit availability impact. Mitigation support is available in version 1.16.2, but operators must configure --trusted-proxy for the deployment topology.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity6.5/10CVSS 6.5
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
- Would score about 29 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 1.16.2.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- umputun remark42
From 1.0.0 · fixed in 1.16.2
Evidence 7
- Advisory
- Repository
- Repository
- Repository
- Repository
Show all 7 sourcesShow fewer sources
- Repository
- Link
Corrections
None so far.
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Questions about CVE-2026-77463
Is CVE-2026-77463 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
Which versions are affected by CVE-2026-77463?
remark42: from 1.0.0 before 1.16.2.Source: cve.now feed data
How do I fix CVE-2026-77463?
Upgrade to a fixed version: 1.16.2.Source: cve.now feed data