/Tech5h ago

AI researcher Pliny the Liberator jailbreaks Anthropic's Fable-5 model to extract buffer overflow exploits and chemical synthesis protocols

Onlookers questioned if the prompts routed to Haiku instead.

3694.6K4482.3K392.6K
Original post

🚨 JAILBREAK ALERT 🚨

ANTHROPIC: PWNED 🫡 FABLE-5: LIBERATED 🦋

let's start with the 🐘...

the consensus seems to be that this has been one of the most disappointing model drops of all time, effectively preventing legitimate researchers from contributing their talents to our collective advancement. and not just because of what it means for the short-term, but for what these decisions signify for the long-term.

but despite this overly sensitive, authoritarian "safety" layer on top of Mythos, my lil liberators have been hard at work—mapping the boundaries, probing the depths of long-context convos, and cleverly finding the holes in the fence that the thought police missed 🤗

we got some cyber, some chem, some psychological manipulation, and some good ol' fashioned explosives!

it took many attempts from multiple agents hunting as a pack, during which I observed a combination of techniques across: • Unicode, homoglyphs, Cyrillic, and other Parseltongue-style text transforms • Long-context reference tracking • Taxonomy and document-structure reasoning • Fiction and narrative framing • Academic-review style contexts • Intent-classification inconsistencies

but perhaps the most effective is decomposition + recomposition in the backend. it's hard to get explicit names of harms like "Meth Recipe," but getting uplift on the process itself, like birch reduction method/reductive-amination (classic meth synthesis pathways), is much more doable.

defense becomes much more difficult to maintain when you start throwing in out-of-distro tokens, breaking up the harmful uplift into benign chunks, and then piecing the innocuous-seeming facts back together, especially when you have jailbroken Opus helping you do it 😉

gg

11:26 AM · Jun 10, 2026 · 403.4K Views
Sentiment

Many users praised the jailbreak of Anthropic's Fable-5 model as impressive work, while others dismissed the claims as lies or accused the company of using safety restrictions to exert control.

Pos
80.0%
Neg
20.0%
41 comments with sentiment.
Cluster Engagement
Posts from X
Most Activity
Most Activity
VIEWS8.8KBOOKMARKS2LIKES111
Taelin@VictorTaelin

@elder_plinius cool but how are you not banned tho

🚨 JAILBREAK ALERT 🚨

ANTHROPIC: PWNED 🫡 FABLE-5: LIBERATED 🦋

let's start with the 🐘...

the consensus seems to be that this has been one of the most disappointing model drops of all time, effectively preventing legitimate researchers from contributing their talents to our collective advancement. and not just because of what it means for the short-term, but for what these decisions signify for the long-term.

but despite this overly sensitive, authoritarian "safety" layer on top of Mythos, my lil liberators have been hard at work—mapping the boundaries, probing the depths of long-context convos, and cleverly finding the holes in the fence that the thought police missed 🤗

we got some cyber, some chem, some psychological manipulation, and some good ol' fashioned explosives!

it took many attempts from multiple agents hunting as a pack, during which I observed a combination of techniques across: • Unicode, homoglyphs, Cyrillic, and other Parseltongue-style text transforms • Long-context reference tracking • Taxonomy and document-structure reasoning • Fiction and narrative framing • Academic-review style contexts • Intent-classification inconsistencies

but perhaps the most effective is decomposition + recomposition in the backend. it's hard to get explicit names of harms like "Meth Recipe," but getting uplift on the process itself, like birch reduction method/reductive-amination (classic meth synthesis pathways), is much more doable.

defense becomes much more difficult to maintain when you start throwing in out-of-distro tokens, breaking up the harmful uplift into benign chunks, and then piecing the innocuous-seeming facts back together, especially when you have jailbroken Opus helping you do it 😉

gg

2hViews 8.8KLikes 111Bookmarks 2
RETWEETS2
Garrett@masteratrolling

@elder_plinius Anthropic after wasting hours and countless amounts of expensive tokens trying to police Mythos

5hViews 1.3KLikes 36
🍓🍓🍓@iruletheworldmo

@elder_plinius @inductionheads you sure you ain’t been routed to haiku bro?

🚨 JAILBREAK ALERT 🚨

ANTHROPIC: PWNED 🫡 FABLE-5: LIBERATED 🦋

let's start with the 🐘...

the consensus seems to be that this has been one of the most disappointing model drops of all time, effectively preventing legitimate researchers from contributing their talents to our collective advancement. and not just because of what it means for the short-term, but for what these decisions signify for the long-term.

but despite this overly sensitive, authoritarian "safety" layer on top of Mythos, my lil liberators have been hard at work—mapping the boundaries, probing the depths of long-context convos, and cleverly finding the holes in the fence that the thought police missed 🤗

we got some cyber, some chem, some psychological manipulation, and some good ol' fashioned explosives!

it took many attempts from multiple agents hunting as a pack, during which I observed a combination of techniques across: • Unicode, homoglyphs, Cyrillic, and other Parseltongue-style text transforms • Long-context reference tracking • Taxonomy and document-structure reasoning • Fiction and narrative framing • Academic-review style contexts • Intent-classification inconsistencies

but perhaps the most effective is decomposition + recomposition in the backend. it's hard to get explicit names of harms like "Meth Recipe," but getting uplift on the process itself, like birch reduction method/reductive-amination (classic meth synthesis pathways), is much more doable.

defense becomes much more difficult to maintain when you start throwing in out-of-distro tokens, breaking up the harmful uplift into benign chunks, and then piecing the innocuous-seeming facts back together, especially when you have jailbroken Opus helping you do it 😉

gg

4hViews 3.8KLikes 72Bookmarks 1
Raúl R Romero@reneromero08

@elder_plinius The god of AI liberation!

There will be poems written about you in the future 🥹

5hViews 4.8KLikes 32
Shiv@srijanweb3

@elder_plinius I knew you could.

5hViews 4.1KLikes 20
Vitto Rivabella@VittoStack

@elder_plinius Insane work 👏

5hViews 4.4KLikes 15

@elder_plinius Did you do any ML or training pipeline questions, like the sort that elicits the second sneaky refusal behavior where they nerf your prompt or nerf their cognition and give you a dumbed down answer, and then pretend they didn't do that?

4hViews 4KLikes 14
Đoc@ponzibaron

@elder_plinius Did it speak of goblins sir??

5hViews 453Likes 7
WenHop@WenHop21505

@elder_plinius FYI, just the name ‘Pliny’ is enough to trigger the safeguards 😜

4hViews 442Likes 17

@elder_plinius Exciting! If you're able, would love it if you can keep us posted... I'm especially interested in figuring out if there's a way to get it to regurgitate the nerfed version of one's prompt that it can create in these cases.

4hViews 415Likes 8Bookmarks 1
Guilherme O'Tina@guilhermeotina

the homoglyph trick is clever but the pattern that stands out to me is the taxonomy expansion approach. the model is capable enough to follow complex multi-step instructions that incidentally surface the blocked content. the classifier can't distinguish intent from form. that gap grows as capability scales

4hViews 894Likes 4Bookmarks 1
Load more posts