CVE-2026-87864: IMAP APPEND plus CRLF conversion command injection
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-04 15:41 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
Enabling `CURLOPT_CRLF` causes curl to advertise the raw input byte count in the `IMAP APPEND {N}` literal while transmitting line-ending expanded data. The server reads only $N$ bytes for the payload, causing the remaining overflow bytes to be interpreted and executed as pipelined IMAP commands within the authenticated session.
Description quoted from the CVE record (assigned by curl, published 2026-10-20).
Weakness: CWE-130 Improper Handling of Length Parameter Inconsistency
How it can be exploited
Exploitable over the network with high attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: no. Technical impact: total.
Public exploit evidence (Exploit Observer)
Exploit Observer found 2 research write-ups naming this CVE.
See all 10 references on Exploit Observer
Live scores
- EPSS
- 0.008
low predicted chance of attack - VEDAS
- 0.987
strong exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| curl | from 8.21.0 up to and including 8.21.0 from 8.20.0 up to and including 8.20.0 from 8.19.0 up to and including 8.19.0 from 8.18.0 up to and including 8.18.0 from 8.17.0 up to and including 8.17.0 from 8.16.0 up to and including 8.16.0 from 8.15.0 up to and including 8.15.0 from 8.14.1 up to and including 8.14.1 and 106 more ranges | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Other references
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
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