Low
IMAP APPEND plus CRLF conversion command injection
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-87864
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 09:38 UTC · Revision 1
Source evidence
IMAP APPEND plus CRLF conversion command injection
core-osv · Original sourcePublished 14 Oct 2026, 08:00 UTC
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.
osv:CURL-CVE-2026-87864
Complete source record
{
"id": "b86adfafc3b6f9faf47727386b82be0a848b812110ffbf5e05ad2dffd16e1752",
"url": "https://osv.dev/vulnerability/CURL-CVE-2026-87864",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "IMAP APPEND plus CRLF conversion command injection",
"summary": "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.",
"evidence": "osv:CURL-CVE-2026-87864",
"products": [],
"severity": "low",
"structured": {
"id": "CURL-CVE-2026-87864",
"aliases": [
"CURL-CVE-2026-87864",
"CVE-2026-87864"
],
"affected": [
{
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{
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{
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"database_specific": {
"source": "https://curl.se/docs/CURL-CVE-2026-87864.json",
"vanir_signatures": [
{
"id": "CURL-CVE-2026-87864-0ce8cfa2",
"digest": {
"length": 2049,
"function_hash": "271163736960417285140970839678364115519"
},
"source": "https://github.com/curl/curl.git/commit/3b547de301342b347fb3c6ea6ae7979070793a66",
"target": {
"file": "lib/imap.c",
"function": "imap_perform_append"
},
"deprecated": false,
"signature_type": "Function",
"signature_version": "v1"
},
{
"id": "CURL-CVE-2026-87864-1bd163f9",
"digest": {
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"line_hashes": [
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"source": "https://github.com/curl/curl.git/commit/3b547de301342b347fb3c6ea6ae7979070793a66",
"target": {
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},
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"signature_type": "Line",
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],
"vanir_signatures_modified": "2026-10-25T01:05:10Z"
}
}
],
"modified": "2026-10-25T01:05:10.991036732Z",
"provider": "osv",
"references": [],
"provider_metadata": {
"CWE": {
"id": "CWE-130",
"desc": "Improper Handling of Length Parameter Inconsistency"
},
"URL": "https://curl.se/docs/CVE-2026-87864.json",
"www": "https://curl.se/docs/CVE-2026-87864.html",
"issue": "https://hackerone.com/reports/3972403",
"affects": "both",
"package": "curl",
"severity": "Low",
"last_affected": "8.21.0"
}
},
"related_cves": [
{
"value": "CVE-2026-87864",
"evidence": "/aliases"
}
],
"security_relevant": true,
"severity_evidence": "/database_specific/severity"
},
"source_id": "core-osv",
"document_id": 444349,
"published_at": "2026-10-14T08:00:00+00:00"
}