MIME::Words versions before 5.521 for Perl allow memory exhaustion via repeated "=?" sequences in decode_mimewords.
For each "=?" that does not start a complete encoded word, decode_mimewords appends an error message containing the whole input string to $@. A boundary of 8,000 "=?" pairs (16,000 bytes) adds 8,000 copies of itself to $@, about 128 MB.
From version 5.518, MIME::Parser decodes every multipart boundary this way, so a remote sender can exhaust the memory of the parsing process with one Content-Type header.
For each "=?" that does not start a complete encoded word, decode_mimewords appends an error message containing the whole input string to $@. A boundary of 8,000 "=?" pairs (16,000 bytes) adds 8,000 copies of itself to $@, about 128 MB.
From version 5.518, MIME::Parser decodes every multipart boundary this way, so a remote sender can exhaust the memory of the parsing process with one Content-Type header.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| unaffected |
|
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Project Subscriptions
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Advisories
No advisories yet.
Fixes
Solution
Upgrade to MIME-tools 5.521 or later.
Workaround
No workaround given by the vendor.
References
| Link | Providers |
|---|---|
| https://metacpan.org/release/DSKOLL/MIME-tools-5.521/changes |
|
History
Wed, 28 Oct 2026 17:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | MIME::Words versions before 5.521 for Perl allow memory exhaustion via repeated "=?" sequences in decode_mimewords. For each "=?" that does not start a complete encoded word, decode_mimewords appends an error message containing the whole input string to $@. A boundary of 8,000 "=?" pairs (16,000 bytes) adds 8,000 copies of itself to $@, about 128 MB. From version 5.518, MIME::Parser decodes every multipart boundary this way, so a remote sender can exhaust the memory of the parsing process with one Content-Type header. | |
| Title | MIME::Words versions before 5.521 for Perl allow memory exhaustion via repeated "=?" sequences in decode_mimewords | |
| Weaknesses | CWE-407 | |
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: CPANSec
Published:
Updated: 2026-10-28T17:33:48.187Z
Reserved: 2026-10-25T18:05:02.236Z
Link: CVE-2026-116270
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-28T18:17:13.470
Modified: 2026-10-28T18:17:13.470
Link: CVE-2026-116270
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses