{"id":"CVE-2026-115774","aliases":["AZL-111416","BELL-CVE-2026-115774","DEBIAN-CVE-2026-115774","EUVD-2026-109148","GHSA-2qrf-pqgx-qh9v","UBUNTU-CVE-2026-115774"],"status":"published","title":"Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH","description":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.","severity":{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.0052,"percentile":0.44702,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-400","CWE-835"],"published":"2026-10-23T20:14:07Z","modified":"2026-11-11T07:30:06Z","fixes":[{"ecosystem":"PyPI","package":"twisted","fixed_in":["26.10.0rc1"],"sources":["ghsa","osv"]},{"ecosystem":"Alpaquita:stream","package":"py3-twisted","fixed_in":["26.10.0-r0"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"twisted","fixed_in":["26.10.0-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"26.4.0"},{"fixed":"26.10.0rc1"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"python-twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"22.10.0-7"}]}]},{"source":"osv","ecosystem":"Alpaquita:stream","package":"py3-twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"22.10.0-r0"},{"fixed":"26.10.0-r0"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["22.4.0-4","22.4.0-4+deb12u1","23.10.0-1","23.10.0-2","24.10.0-1","24.10.0-2","24.11.0-1","24.3.0-1","24.3.0-2","24.3.0-3","24.7.0-1","24.7.0-2","24.7.0-3","25.5.0-1","25.5.0-2","25.5.0-3","25.5.0-4","25.5.0-5","26.10.0-1","26.4.0-1","26.4.0-2","26.4.0-3","26.4.0-4","26.4.0-5","26.4.0-6"]},{"source":"osv","ecosystem":"Debian:13","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["24.11.0-1","25.5.0-1","25.5.0-2","25.5.0-3","25.5.0-4","25.5.0-5","26.10.0-1","26.4.0-1","26.4.0-2","26.4.0-3","26.4.0-4","26.4.0-5","26.4.0-6"]},{"source":"osv","ecosystem":"Debian:14","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"26.10.0-1"}]}],"versions":["24.11.0-1","25.5.0-1","25.5.0-2","25.5.0-3","25.5.0-4","25.5.0-5","26.4.0-1","26.4.0-2","26.4.0-3","26.4.0-4","26.4.0-5","26.4.0-6"]},{"source":"osv","ecosystem":"PyPI","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"26.10.0rc1"}]}],"versions":["1.0.1","1.0.3","1.0.4","1.0.5","1.0.6","1.0.7","1.1.0","1.1.1","1.2.0","10.0.0","10.1.0","10.2.0","11.0.0","11.1.0","12.0.0","12.1.0","12.2.0","12.3.0","13.0.0","13.1.0","13.2.0","14.0.0","14.0.1","14.0.2","15.0.0","15.1.0","15.2.0","15.2.1","15.3.0","15.4.0","15.5.0","16.0.0","16.1.0","16.1.1","16.2.0","16.3.0","16.3.1","16.3.2","16.4.0","16.4.1","16.5.0","16.5.0rc1","16.5.0rc2","16.6.0","16.6.0rc1","16.7.0rc1","16.7.0rc2","17.1.0","17.1.0rc1","17.5.0","17.9.0","17.9.0rc1","18.4.0","18.4.0rc1","18.7.0","18.7.0rc1","18.7.0rc2","18.9.0","18.9.0rc1","19.10.0","19.10.0rc1","19.2.0","19.2.0rc1","19.2.0rc2","19.2.1","19.7.0","19.7.0rc1","2.1.0","2.4.0","2.5.0","20.3.0","20.3.0rc1","21.2.0","21.2.0rc1","21.7.0","21.7.0rc1","21.7.0rc2","21.7.0rc3","22.1.0","22.1.0rc1","22.10.0","22.10.0rc1","22.2.0","22.2.0rc1","22.4.0","22.4.0rc1","22.8.0","22.8.0rc1","23.10.0","23.10.0rc1","23.8.0","23.8.0rc1","24.10.0","24.10.0rc1","24.11.0","24.11.0rc1","24.11.0rc2","24.2.0rc1","24.3.0","24.7.0","24.7.0rc1","24.7.0rc2","25.5.0","25.5.0rc1","26.4.0","26.4.0rc2","8.0.0","8.0.1","8.1.0","8.2.0","9.0.0"]},{"source":"osv","ecosystem":"Ubuntu:Pro:14.04:LTS","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["13.0.0-1ubuntu1","13.2.0-1ubuntu1","13.2.0-1ubuntu1.2","13.2.0-1ubuntu1.2+esm1","13.2.0-1ubuntu1.2+esm2","13.2.0-1ubuntu1.2+esm3"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["15.2.1-1ubuntu2","15.5.0-1","15.5.0-2","15.5.0-2ubuntu1","15.5.0-4","16.0.0~pre1-1","16.0.0~pre1-1ubuntu1","16.0.0~pre1-2ubuntu1","16.0.0~pre1-3","16.0.0-1","16.0.0-1ubuntu0.2","16.0.0-1ubuntu0.4","16.0.0-1ubuntu0.4+esm1","16.0.0-1ubuntu0.4+esm2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["16.6.0-2ubuntu3","17.9.0-1","17.9.0-2","17.9.0-2ubuntu0.1","17.9.0-2ubuntu0.3","17.9.0-2ubuntu0.3+esm1","17.9.0-2ubuntu0.3+esm2"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["18.9.0-3ubuntu1","18.9.0-5","18.9.0-6","18.9.0-6build1","18.9.0-6ubuntu1","18.9.0-8","18.9.0-11","18.9.0-11ubuntu0.20.04.1","18.9.0-11ubuntu0.20.04.2","18.9.0-11ubuntu0.20.04.3","18.9.0-11ubuntu0.20.04.4","18.9.0-11ubuntu0.20.04.5"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["20.3.0-7ubuntu1","20.3.0-7ubuntu3","22.1.0-2ubuntu2","22.1.0-2ubuntu2.1","22.1.0-2ubuntu2.3","22.1.0-2ubuntu2.4","22.1.0-2ubuntu2.5","22.1.0-2ubuntu2.6","22.1.0-2ubuntu2.7","22.1.0-2ubuntu2.8"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["22.4.0-4","22.4.0-4ubuntu1","23.10.0-2","24.3.0-1","24.3.0-1ubuntu0.1","24.3.0-1ubuntu0.2","24.3.0-1ubuntu0.3"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["25.5.0-5","26.4.0-4","26.4.0-4ubuntu0.1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"twisted","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["24.11.0-1","25.5.0-4","25.5.0-5","25.5.0-5ubuntu0.1","25.5.0-5ubuntu0.2"]}],"products":[{"vendor":"twisted","product":"twisted"}],"references":[{"url":"https://github.com/twisted/twisted/security/advisories/GHSA-2qrf-pqgx-qh9v","tags":["x_refsource_CONFIRM","exploit","advisory","web","report"]},{"url":"https://github.com/twisted/twisted/pull/12764","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/twisted/twisted/commit/3d125548bcbe955007cb97f480bb699a5e074741","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1","tags":["x_refsource_MISC","web","report"]},{"url":"https://github.com/advisories/GHSA-2qrf-pqgx-qh9v"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-115774","tags":["web","advisory"]},{"url":"https://docs.bell-sw.com/security/cves/CVE-2026-115774","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/115xxx/CVE-2026-115774.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-115774","tags":["advisory"]},{"url":"https://github.com/twisted/twisted","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-115774","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-115774","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-115774","title":"Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH","description":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.","status":"published","published":"2026-10-23T20:14:07.48Z","modified":"2026-10-29T14:20:15.738Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-400","CWE-835"],"updated_at":"2026-11-02T14:20:01.969981Z"}],"euvd":[{"id":"EUVD-2026-109148","description":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.","status":"published","published":"2026-10-23T20:14:07Z","modified":"2026-10-29T14:20:15Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T16:59:16.484344Z"}],"ghsa":[{"id":"GHSA-2qrf-pqgx-qh9v","title":"Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH","description":"## Summary\n\nAn infinite-loop vulnerability (CWE-835) in the Twisted IMAP4 server lets an authenticated client freeze the whole process with one small command. `twisted.mail.imap4.parseNestedParens` reads an IMAP literal size with `int()` and never rejects a negative value. A negative size such as `{-100}` drives the parser cursor negative, and because a negative Python index wraps around the end of the string instead of raising, the scanning loop never terminates. It runs synchronously on the single-threaded reactor, so one `SEARCH` command holds the reactor at full CPU forever and every other connection stops being served.\n\n## Details\n\nMeeting an inline literal, `parseNestedParens` reads the size between the braces and advances the cursor past the body:\n\n```python\n# twisted/mail/imap4.py  parseNestedParens\nliteralSize = int(s[i + 1 : end])          # no sign check\ncontentStack[-1].append((s[end + 3 : end + 3 + literalSize],))\ni = end + 3 + literalSize                    # negative size -\u003e i goes negative\n```\n\n`int(b\"-100\")` is `-100`, so `i` goes negative; the loop condition `i \u003c len(s)` stays true and `s[i : i + 1]` on a negative index never raises, so the cursor cycles forever. The `_literalStringLimit` guard only covers the synchronizing-literal continuation path, not this inline branch. The call is reached from `select_SEARCH` through `arg_searchkeys`, dispatched only in the selected state, so a valid login and a selected mailbox (any low-privilege account) suffice. It runs in the reactor thread, and the connection timeout cannot fire because the reactor itself is frozen.\n\nAffected product: Twisted (`twisted.mail`), the IMAP4 server `twisted.mail.imap4.IMAP4Server`\nAffected versions: 26.4.0 and earlier\n\n## PoC\n\nLog in, select a mailbox, and send a `SEARCH` whose literal size is negative:\n\n```text\nC: t1 LOGIN testuser password-test\nC: t2 SELECT INBOX\nC: t3 SEARCH {-100}zzzzzzzzzz\n```\n\nThe server never responds and one core stays at 100 percent. In a measured run a health service co-hosted on the same reactor stopped answering the instant the command arrived, showing the freeze hits the whole process and not just the attacking connection. A valid `{5}zzzzz` completes normally and a non-numeric `{abc}` is rejected with a parse error, which isolates the cause to the missing negative-size check.\n\n## Impact\n\nA remote denial of service. One command of about ten bytes freezes the single-threaded reactor, so it stops serving not only every other IMAP connection but every other service co-hosted in the same process (for example SMTP and POP3 under `twistd mail`), and no timeout can recover it until the process is restarted. It requires an authenticated session, so any account holder can trigger it; there is no confidentiality or integrity impact and no code execution.","status":"published","published":"2026-10-23T20:46:12Z","modified":"2026-10-23T20:46:13Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-400","CWE-835"],"updated_at":"2026-11-02T14:41:35.723785Z"}],"nvd":[{"id":"CVE-2026-115774","description":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.","status":"published","published":"2026-10-23T21:17:22.9Z","modified":"2026-10-29T15:17:18.58Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-400","CWE-835"],"updated_at":"2026-11-02T14:13:03.126833Z"}],"osv":[{"id":"BELL-CVE-2026-115774","status":"published","published":"2026-10-28T06:08:00.134139Z","modified":"2026-11-11T07:30:06.185608096Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-11T07:56:32.232974Z"},{"id":"CVE-2026-115774","title":"Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH","description":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.","status":"published","published":"2026-10-23T20:14:07.48Z","modified":"2026-10-31T02:30:37.098513894Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-400","CWE-835"],"updated_at":"2026-11-02T15:44:56.675758Z"},{"id":"DEBIAN-CVE-2026-115774","description":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.","status":"published","published":"2026-10-23T21:17:22.9Z","modified":"2026-11-02T12:03:13.090695653Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:50.923612Z"},{"id":"GHSA-2qrf-pqgx-qh9v","title":"Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH","description":"## Summary\n\nAn infinite-loop vulnerability (CWE-835) in the Twisted IMAP4 server lets an authenticated client freeze the whole process with one small command. `twisted.mail.imap4.parseNestedParens` reads an IMAP literal size with `int()` and never rejects a negative value. A negative size such as `{-100}` drives the parser cursor negative, and because a negative Python index wraps around the end of the string instead of raising, the scanning loop never terminates. It runs synchronously on the single-threaded reactor, so one `SEARCH` command holds the reactor at full CPU forever and every other connection stops being served.\n\n## Details\n\nMeeting an inline literal, `parseNestedParens` reads the size between the braces and advances the cursor past the body:\n\n```python\n# twisted/mail/imap4.py  parseNestedParens\nliteralSize = int(s[i + 1 : end])          # no sign check\ncontentStack[-1].append((s[end + 3 : end + 3 + literalSize],))\ni = end + 3 + literalSize                    # negative size -\u003e i goes negative\n```\n\n`int(b\"-100\")` is `-100`, so `i` goes negative; the loop condition `i \u003c len(s)` stays true and `s[i : i + 1]` on a negative index never raises, so the cursor cycles forever. The `_literalStringLimit` guard only covers the synchronizing-literal continuation path, not this inline branch. The call is reached from `select_SEARCH` through `arg_searchkeys`, dispatched only in the selected state, so a valid login and a selected mailbox (any low-privilege account) suffice. It runs in the reactor thread, and the connection timeout cannot fire because the reactor itself is frozen.\n\nAffected product: Twisted (`twisted.mail`), the IMAP4 server `twisted.mail.imap4.IMAP4Server`\nAffected versions: 26.4.0 and earlier\n\n## PoC\n\nLog in, select a mailbox, and send a `SEARCH` whose literal size is negative:\n\n```text\nC: t1 LOGIN testuser password-test\nC: t2 SELECT INBOX\nC: t3 SEARCH {-100}zzzzzzzzzz\n```\n\nThe server never responds and one core stays at 100 percent. In a measured run a health service co-hosted on the same reactor stopped answering the instant the command arrived, showing the freeze hits the whole process and not just the attacking connection. A valid `{5}zzzzz` completes normally and a non-numeric `{abc}` is rejected with a parse error, which isolates the cause to the missing negative-size check.\n\n## Impact\n\nA remote denial of service. One command of about ten bytes freezes the single-threaded reactor, so it stops serving not only every other IMAP connection but every other service co-hosted in the same process (for example SMTP and POP3 under `twistd mail`), and no timeout can recover it until the process is restarted. It requires an authenticated session, so any account holder can trigger it; there is no confidentiality or integrity impact and no code execution.","status":"published","published":"2026-10-23T20:46:12Z","modified":"2026-10-23T21:00:04.322993195Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-400","CWE-835"],"updated_at":"2026-11-02T15:46:34.700741Z"},{"id":"UBUNTU-CVE-2026-115774","description":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.","status":"published","published":"2026-10-23T21:17:00Z","modified":"2026-11-05T11:46:54.463518816Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-05T13:30:15.321876Z"},{"id":"AZL-111416","title":"CVE-2026-115774 affecting package python-twisted 22.10.0-7","description":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.","status":"published","published":"2026-10-23T21:17:22Z","modified":"2026-11-05T05:40:51Z","updated_at":"2026-11-05T16:41:18.705965Z"}]}}